When Malvin Cavalier fled to the Superdome as Hurricane Katrina bore down on his home in the 9th Ward of New Orleans, he left a bucket of food and pail of water on the front porch for his poodle, Bandit.

"I figured, 'I'll be in the Superdome, the storm hits, I'll be back in a couple of days, go back home and Bandit'll be there and everything will be normal again,' " Mr. Cavalier said.

That was Aug. 28.

Today, Mr. Cavalier is living in an apartment in Houston, waiting for a new home in New Orleans. Bandit was last seen somewhere in the Pittsburgh area, brought here by the head of a local animal rights group and given to a woman whose attorney has suggested Mr. Malvin, 86, was unfit to care for the animal.

"It's my dog. She has no right to it. That's just stealing," Mr. Cavalier said.

The battle pits Mr. Cavalier, a retired sheet-metal worker and widower, against Lisa Fox, whose last address was in McCandless. Mr. Cavalier's attorney has been unable to find her.

Eric Rice, an Annapolis, Md., businessman who joined in animal rescues after Katrina, said he has encountered hundreds of cases of shelters that put up pets for adoption without first attempting to find owners, as well as cases of advocacy groups that simply assume any pet left behind was neglected.

"There's a set of animal rescue people out there that are so far into the animal side of it that they're not into the people side of it," said Mr. Rice, who has used his Web site, ericsdogblog.com, to reunite pets and their owners.

In his lawsuit, Mr. Cavalier says Ms. Fox obtained the dog from Peter McKosky, a leader in Voices for Animals of Western Pennsylvania. Mr. McKosky, the complaint adds, picked up Bandit along with other animals at a rescue center set up after thousands of pets were recovered amid the wreckage of the city.

The complaint says Mr. McKosky was supposed to take his finds to Chenoa Manor, a Chester County rescue shelter, pending reunification with their owners. Mr. McKosky has since left his home in Belle Vernon, according to his father, who says he has not been in touch. He did not return several messages left on his cell phone requesting comment.

Other long-distance custody fights have erupted over pets left behind during Katrina, often by owners who were told not to take their pets with them to the Superdome.

"It's a fairly national problem," said Scott Hendler, an Austin, Texas, lawyer who last week had a Rottweiler puppy returned to Catherine and William Taylor. Mr. Hendler filed suit in Texas after a rescue group there, called Rottielove, failed to return the puppy to the Taylors and instead arranged for a Texas woman to adopt it.

"It was just a question of the rescuers deciding for themselves that the puppy would be better off with a family that could take it now instead of waiting three weeks until the original owners were in a position to reclaim it," Mr. Hendler said. "The original owners had three or four dogs. I think there were lots of assumptions made about their ability to care for the animals that weren't legitimate."

Similar disputes over unreturned pets have arisen in New Jersey and Illinois. The Louisiana attorney general's office has assigned a deputy to attempt to negotiate the return of pets whose rescuers have decided to keep them. No one has kept a definite record of how many pets were displaced by Katrina. Before the storm, according to an estimate by the American Society for the Prevention of Cruelty to Animals, the animal population of the Gulf area was 205,000 dogs, 230,000 cats, 46,000 birds and 2,000 horses.

At least 4,926 animals went through one staging area for rescued pets in Gonzales, La. An estimated 15,000 animals were rescued by more than 400 groups.

The mix of emotions and ideology that often accompany pets and the groups that advocate for them has put Mimi Hunley, the deputy attorney general in Louisiana assigned to deal with the disputes, in a difficult spot. Louisiana will not file suit on behalf of individuals and cannot file a class action because so many organizations are involved in the pet rescues.

"In these particular cases, there's not one defendant. There's just various shelters all over the country," Ms. Hunley said. She has negotiated for the return of at least 15 animals.

Bandit was among the early cases, and one that ended in frustration.

"I reached a point in the negotiations where I was not accomplishing anything with these people. I did not feel I was making any headway," she said.

At the time, the negotiations were taking place between Carolyn Flamm, a Pittsburgh lawyer who, she said, represented Ms. Fox and Voices for Animals, and Sandra Bauer, a Canadian animal rights activist who is affiliated with a group called Stealth Rescue. Ms. Bauer's group had been attempting to reunite pets and their owners.

"It sort of spiraled out of control," Ms. Hunley said. Ms. Bauer found a lawyer for Mr. Cavalier and negotiations stopped.

Ms. Bauer declined to comment about the fight.

Ms. Flamm declined to discuss the matter other than to say further negotiations were scheduled.

"We are attempting settlement negotiations and I think there's a good chance we will settle this amicably," she said.

She declined to say whether Bandit was still in the Pittsburgh area.

Voices for Animals of Western Pennsylvania has gained attention by picketing restaurants that serve goose liver pate and setting up protests outside the Shrine Circus, which it views as an abuser of animals. The group promotes a meat-free diet, objects to hunting and protested last year's Bassmaster Classic Fishing Tournament on Pittsburgh's three rivers.

Its Web site offers this statement of beliefs: "We envision a society where animals are viewed as respected members of our communities, rather then being seen as mere human-owned commodities. Our goal is to educate the Western Pennsylvania community about issues affecting animals and encourage ethical and sustainable lifestyle choices that reflect an underlying ethic of compassion and respect for all sentient beings -- regardless of race, class, sexual orientation, gender, age or species."

According to the lawsuit, Bandit came into the hands of Voices for Animals when Mr. McKosky traveled to Gonzales, La., where displaced pets were being sheltered.

"Mr. McKosky represented himself as an authorized agent" of Chenoa, and left with numerous pets. Instead of taking Bandit to Chenoa, the complaint says, "Mr. McKosky retained possession of Bandit for himself" and later "refused to return Bandit, suggesting that the elderly Mr. Cavalier was irresponsible in 'abandoning' Bandit, and thus an undeserving owner."

One member of Stealth Rescuers, Cindi Nicotera, a Harrisburg, Pa., librarian, said she first contacted Mr. McKosky about a pet cat she believes the group also took from New Orleans after Katrina.

"He just went off and said those people don't deserve to have these pets and none of these pets is going back to New Orleans. He was screaming at me most of the time," Mrs. Nicotera said. "He's going on about how he would never leave his animals."

Mr. Cavalier said he was forbidden to take his dog with him to the Superdome. Instead, he left of food and water and propped his front door open to allow Bandit to move in and out at will.

"I didn't have any idea I'd be in the Superdome six days, sir. I didn't know the levee was going to break," he said.

According to the complaint, Mr. McKosky gave Bandit to Voices for Animals in the fall or winter last year and the group, in turn, gave the dog to Ms. Fox.

Mr. Cavalier, who says Bandit is the last remnant of the life he shared with his wife, who died in 2003 after 54 years of marriage, has a new home waiting in the 9th Ward, once the government sets up a mobile home on his now-cleared lot.

"I'm going to try to get my dog back and take my dog with me everywhere I go," he said. "Before this year's out, I'm going home to New Orleans, and I'll have Bandit with me."