Port Authority police are collecting writing samples and questioning employees in an effort to determine who hanged a black baby doll daubed with a racist threat in a hallway at its East Liberty garage.

Port Authority spokesman Bob Grove said an "item" found hanging early yesterday near the entrance to the garage had been turned over to police. A union leader and others identified it as a doll and said it bore an epithet directed at an unspecified black woman.

Police intend to file criminal charges if they identify the person responsible, Mr. Grove said. Management officials from the Port Authority's office of equal opportunity met with groups of garage employees on each shift yesterday to advise them that the "reprehensible" incident is under investigation and will not be tolerated, he said.

"We do not condone this type of behavior in our workplace and we are doing everything possible to find out who did this," Mr. Grove said. "We will prosecute anyone determined to be responsible."

Employees found the doll hanging near the maintenance shop, in an employee-only area of the complex, when they arrived for work between 3 and 4 a.m. yesterday. Mr. Grove and Patrick McMahon, president-business agent of the union representing Port Authority bus and trolley employees, said investigators have not determined who specifically was the target or what may have precipitated the incident.

"That's one of the things the police investigation and, hopefully, our employee meetings will flesh out," Mr. Grove said.

Mr. Grove and Mr. McMahon said they did not know if the incident was related to recent personnel shifts resulting from annual opportunities for employees to bid on locations where they work or to finance-driven layoffs earlier this year. Bus operators picked new work locations last month; maintenance workers picked in July, Mr. Grove said.

About two weeks ago, Mr. McMahon said, "there was some tension" at the East Liberty garage after some employees balked at training new employees there, which is their right under their labor contract. He said he believed those issues had no racial overtones and were being worked out.

"As far as it being racial, I haven't heard that," he said. "I'm hearing different things about this, but nothing concrete. There are more than 500 employees there and it's still kind of vague who [it was ] directed at."

Mr. McMahon acknowledged that the culprit likely was an employee because the doll was hanging in an area beyond the garage complex's guarded entrances. He said he and other union leaders are planning their own series of visits with garage employees to stress their revulsion over the "absolutely unacceptable" incident.

"This is upsetting, just a very upsetting thing. It's so unfortunate that, in today's world, we have people who are so ugly and small-minded," he said. "To me, there is no room for that kind of nonsense."