WATERLOO, Illinois (CNN) -- A southwestern Illinois man accused of strangling his wife and two young sons did not ask how his family was killed or see their bodies after he learned of the deaths, a police official said at a preliminary hearing Wednesday.
Christopher Coleman has pleaded not guilty and is being held without bond.
Christopher Coleman, 32, is charged with three counts of first-degree murder in the deaths of Garett, 11, Gavin, 9, and his wife, Sheri Coleman, 31.
The victims were strangled in their beds last month.
A pathologist will testify during the trial that the time of deaths May 5 was between 11 p.m. and 3 a.m., hours before Coleman said he drove to a gym, said Chief Joe Edwards of the Columbia Police Department.
Coleman, a security supervisor, was arrested May 19.
The chief also said that a handwriting expert has concluded that the profanity-laced messages scrawled in red spray paint throughout the house match Coleman's handwriting. Spray-painted messages were also found on Gavin's bed sheets, he said. Watch more on the profane messages »
Threatening letters left in the family's mailbox and an e-mail allegedly sent to Coleman before the killings were traced back to the suspect's laptop, he said. The letters had no envelopes and no postage, according to Edwards.
Testifying at a hearing at the Monroe County Courthouse, the chief said that a police chaplain noticed an abrasion on Coleman's right arm as he was escorted to an ambulance after the bodies were discovered.
Coleman then repeatedly punched the gurney with the arm, Edwards said, adding that when the suspect's father asked him about the abrasion, he said it was from punching the gurney.
The suspect was having an affair with a friend of his wife who lives in Florida, according to prosecutors.
Computer forensics found videos, photos and messages between the two, Edwards said.
Coleman pleaded not guilty to all charges. The next court date is set for August 26.