PORTLAND – A University of Southern Maine art exhibit that showcases the paintings of a prison inmate who murdered a New Jersey state trooper 25 years ago has caused an uproar among police in Maine.

Police said organizers of the exhibit, “Can’t Jail the Spirit,” painted an unfair picture of artist Thomas Manning, a self-styled revolutionary who committed a spate of bombings and is serving 80 years for the 1981 killing of Trooper Philip Lamonaco after a traffic stop on Interstate 80.

Critics expressed particular outrage at the Woodbury Campus Center exhibit’s portrayal of Manning, a former Portland resident, as a political prisoner, saying it glosses over his violent past.

“Here is a person who created a group that targeted government buildings. Here they are being provided a favor by a government-funded school,” George Loder, vice president of the Maine State Trooper Association, said Wednesday.

Organizers of the exhibit said Manning’s work sheds light on the often ignored subject of political prisoners. Among the paintings being displayed are a self-portrait and other works showing black activist Malcolm X’s widow, Betty Shabazz, and a group of women from Chiapas, Mexico, where indigenous residents have battled the government.

Raymond Levasseur, an ex-convict who also describes himself as a former political prisoner, helped organize the display. He said Manning’s works are “reflective of the humanity of the struggles we identify with.”

Police condemnation prompted USM officials to alter the exhibit’s promotional materials, which described Manning as a “Vietnam veteran, working class revolutionary and U.S. political prisoner.”

The term “political prisoner” has since been placed in quotes and qualifying statements such as “self-described” added to reflect differences of opinion on Manning, said USM spokesman Robert Caswell.

“The original materials should have more clearly made the point that USM is not defining Mr. Manning as a political prisoner,” Caswell said.

Loder said labeling Manning a political prisoner was disrespectful to the slain trooper and putting quotes around the offending terms after-the-fact did little to assuage his association’s concerns, which he has spelled out to university officials and corporate sponsors.

Police have not yet decided whether to protest the exhibit’s opening reception, which is scheduled for Sept. 15, he said.

Levasseur, 59, who returned to Maine following his release from federal prison in 2004, said he does not think public universities should back down when pressured by corporations and police.

Levasseur and Manning, under the auspices of the United Freedom Front, were convicted of bombings at military installations and business buildings, some of which targeted companies that worked with South Africa’s apartheid government.

Carolyn Eyler, director of exhibitions and programs at USM’s art galleries, said members of an advisory committee engaged in heated debate over whether to invite the exhibit to campus.

She said they decided to bring the exhibit in hopes it sparks discussion about whether violence is ever appropriate in political movements and whether Manning is, as his supporters claim, a U.S. political prisoner.