Police charged a pair of students from the Art Institute of Pittsburgh with a year-long graffiti spree that caused more than $94,000 in damage and ended only after one of them "tagged" the store shelf from which they stole a pen.

"These gentlemen were looking at etching pens. And of course one stole one and the other one on the way out had to leave his mark on the shelf. So he left his tag on the shelf," said Detective Frank Rende, a member of the city graffiti task force.

The store, in North Versailles, prosecuted the men for shoplifting and the one suspect's graffiti name -- "Toaster" -- turned up on a city vandalism database.

Members of the city's three-man graffiti task force, which includes Detective Rende as well as Detectives Dan Sullivan and Alfonso Sloan, carried out a search warrant at the Art Institute dormitory, just a block from the city jail, and found evidence linking the two students to graffiti across the city.

Charged were Bryan Stafford, 19, who tagged buildings and walls with the names "Sine" and "Sine One," and his partner, Terrell M. Crawford, 19, who used the names "Toast" and "Toaster."

The two are being held in the Allegheny County Jail on two felony counts.

"If I use the word artist, kick me in my shin," Detective Rende said to police spokeswoman Diane Richard as he began an afternoon press conference that laid out the graffiti case.

Police say the men traveled throughout the city with cans of spray paint.

"They were doing it on railings, mailboxes, buildings, garage doors, business fronts, rooftops -- they were pretty rampant," said Detective Rende. He said the pair even spray-painted a highway underpass where the homeless resided.

An estimated $15,000 of the damage was done to property of the Norfolk-Southern Railway, police said.

After a search warrant turned up evidence linking the pair to the graffiti, Detective Rende said, "they came in for an interview. They confessed that they are Toaster and Sine One."

The city has spent 2008 cracking down hard on graffiti vandals.

In July, Daniel Montano, a Highland Park graffitist, was sentenced to 2 1/2 to 5 years in state prison after pleading guilty to 79 counts of criminal vandalism.

Detective Rende said task force members had hoped the Montano case would scare off future graffiti squads. Yesterday he pleaded for the public to keep an eye out for graffiti vandals and to notify police.

"If you see a kid out there with a backpack at 11 o'clock at night and a tossel cap and a hooded sweatshirt, he's not going to study with his friends," he said. "There's a good chance he has paint cans in that bag."