TAMMS, Ill. (CBS) — An inmate at an Illinois maximum security prison serving a life sentence is in trouble over a drawing celebrating life.

As WBBM Newsradio’s Nancy Harty reports, Corey Fox’s drawing of a newborn made him a bit of a celebrity at the Tamms Correctional Center in Southern Illinois, and helped sell at least one T-shirt benefiting TLC Pregnancy Center in Elgin.

LISTEN: WBBM Newsradio’s Nancy Harty reports

His detailed ink sketch shows an infant in an incubator and includes a caption reading, “Pro-Life,” according to the Belleville News-Democrat.

But prison officials are not happy that Fox, a convicted killer, may have violated the rules. They are now launching an investigation into whether he might have engaged in an “unauthorized business venture,” having started up an online account called “Corey’s Pro-Life Store,” the newspaper reported.

Supporters say Fox will not benefit financially from the picture, and was just trying to do a good thing.

Fox, 36, stabbed a man to death in downstate East Alton. He was held at the Madison County Jail while awaiting trial, and had allegedly planned to escape by throwing pencil shavings at a guard’s eyes, then choking him with a blanket he wound fashion into a rope, according to the News-Democrat.

After he was convicted, Fox strangled his 22-year-old cellmate at the Menard Correctional Center, and was transferred to the supermax Tamms facility, the News-Democrat reported.