COLUMBIA, Ill. — A glove found along Interstate 255 may be a key clue to who killed Sheri Coleman and her two sons in their home here, law enforcement sources said Monday.

They said the glove appeared to have stains from red spray paint. A similar color paint was used by the killer to scrawl a message on a wall in the Coleman home.

Investigators are testing the glove for fingerprints and DNA, the sources said, and otherwise checking whether it can be linked to the crime scene.

Coleman, 31, and sons Garett, 11, and Gavin, 9, were found dead in their bedrooms May 5. Neighbors told reporters that police said the victims were strangled, although no official cause of death has been reported.

Christopher Coleman, the surviving husband and father, told detectives he left home around 5:45 a.m. that day to go to a gym in south St. Louis County. He called police shortly before 7 a.m., worried that he could not reach his family by phone and asking that officers check their well-being. Police found the bodies.

Within several days, investigators walked stretches of Interstate 255 near the Jefferson Barracks Bridge, checking the roadsides for something. They wouldn't disclose what.

Last week, police announced they had identified a lone killer who targeted the family, and turned evidence over to Monroe County State's Attorney Kris Reitz. He has deferred a decision on charges, pending unspecified forensic tests.

William Margulis, the attorney representing Christopher Coleman, declined to comment Monday about the glove.

It was found along what would have been Coleman's route to the gym. Police have not named him as a suspect. His fingerprints were taken by court order last week, and he was under obvious police surveillance for a while.

Asked for comment about the glove, Major Case Squad commander Jeff Connor responded that it "is not a confirmed piece of evidence."

Police sources have said that someone painted words on the wall to the effect of, "I told you this would happen."

Christopher Coleman told police he had received some kind of threats in his role as a security manager for Joyce Meyer, an internationally known televangelist based in Jefferson County. He resigned from the job last week; a Joyce Meyer Ministries spokesman on Monday cited "a violation of moral conduct" but declined to give specifics about Coleman's resignation.

Police sources have said that investigators interviewed a woman in Florida who had been a friend of Sheri Coleman's in high school and who was involved in a recent romance with Christopher Coleman, meeting him sometimes when he traveled on business. His lawyers have declined to comment on that.