Jack Ronald Jones, facing a possible death sentence for the murder of Frostburg State College art student Stephanie Ann Roper, was portrayed today as a remorseful sinner whose mental faculties may have been substantially impaired by drugs and alcohol the night of the crime.

Jones, 26, could be executed unless the same jury that found him guilty last week concludes in this second phase of the proceeding that mitigating circumstances justify life imprisonment.

In testimony today by a psychiatrist, a minister and members of Jones' immediate family, the defendant's lawyers tried to show that the April 3 abduction, rape and murder in Southern Maryland was an aberration in the troubled but not normally violent life of Jones.

The jury heard his wife, Laurie, describe him as a "very good person" who was close to their 6-year-old son, with whom he often went bike riding and played ball. It was only when he was under the influence of drugs, she said, that "I couldn't reason with him" and he was "very short-tempered . . . just rowdy."

Afer his incarceration for the crime, she acknowledged under cross-examination, she tried to smuggle tranquilizers to him in jail. Subsequently, she pleaded guilty to possession with intention to distribute controlled dangerous substances and received two years probation.

Explaining her actions, Laurie Jones said her husband "was very, very upset and was having a great deal of difficulty sleeping. He was very, very sorry for what he'd done and for what he'd also done to his family."

According to trial testimony by codefendant Jerome Lee Beatty, 17, he and Jones had been mixing beer and drugs for several hours before they happened upon Roper in her disabled car on a lonely road in rural Prince George's County. Instead of taking her to a friend's home as promised, Beatty said they drove her to an abandoned house in St. Mary's County, where they repeatedly raped her and Jones struck her with a logging chain, shot her in the forehead and set her afire. Beatty faces his own trial next week.

Today, Joseph R. Jones Sr., the father of the convicted murderer, said he knew of his son's drug problem but "I could never talk to Jack. I'd start to talk to him about it, but it would always end up in an argument of some sort."

The senior Jones said he had two other sons and his wife had 13 children by a former marriage, several of whom lived, off and on, with the financially struggling family.

Jack, he said, left home at 16 or 17 and lived for a while at the Brandywine Volunteer Fire Department, where he received two plaques for responding to the most calls for help during that time.

Dr. Brian Crowley, a Bethesda psychiatrist, testified that Jones had come from an "emotionally impoverished background" but had a "high average potential intelligence" and was "capable of feelings of remorse and guilt. I believe his mental faculties were substantially impaired as a result" of the use of alcohol and drugs, he said. "I don't believe he will pose a continuing threat to society for a long period of time, if ever."

The Rev. Cleveland H. Goode, a prison chaplain who has counseled Jones, said the unemployed father "cried and wept for 45 minutes" during their first visit. Goode said Jones "committed his life to the Lord Jesus Christ that very day."

Goode said that Jones, responding to a scriptural assignment, wrote shortly afterwards, "My feelings towards others have changed from hatred to love, and my outlook on life has greater meaning because I am a child of God."

With emotions at a fever pitch as the proceeding entered its fifth week, the father of the victim was admonished by Circuit Judge Walter R. Haile to maintain "conduct above reproach" after Gary Bair, one of Jones' attorneys, alleged that Vincent Roper assaulted him in the hallway during a recess.

"I slipped when I was going near him," Stephanie Roper's father said. "I subsequently apologized. It's close quarters out there. If it's deemed as being an assault, I apologize for my conduct."