"No sir. I didn't."

With that flat, unequivocal response, Steven Ray James took the witness stand Tuesday and Wednesday, denying he murdered his 3-month-old son, Steven Roy James.James described himself as a "learning father - but a happy father" - a father who deeply loved his son, enjoyed tending him, showed off his namesake's photo to strangers - and still looks for the kidnapper who murdered his child.

During two days of testimony, James six times denied killing his baby.

Prosecutors, however, were unswayed.

"I suggest you know who wrapped the baby in a cloth weighted down with rocks and dropped him down in the river, don't you?" asked prosecutor James Jenkins.

"No, I don't," replied James.

The defendant suggested that an Arizona man to whom he owed money for drugs murdered his son as revenge.

James is on trial in Salt Lake's 3rd District Court on a first-degree murder charge in the death of Steven Roy James. The father reported his son missing Aug. 26, l986, saying the boy had been kidnapped from his car while he shopped at a Logan drug store.

Forty-six days later, duck hunters discovered the infant's body in a marsh, wrapped in a bundle tied with an electrical cord and weighted by five heavy rocks.

Speaking in a matter-of-fact tone, displaying no noticeable emotion, James denied one-by-one allegations made in previous testimony by his girlfriend, Victoria DeLeon, who claimed James had beaten their infant son.

He explained the bruises discovered on the boy before he turned up "missing" as being "accidents" - natural occurrences that occur in tending an active child.

DeLeon had also testified that James had, in effect, admitted the murder by stating "I didn't mean to do it" on Aug. 26, 1986.

In response, James claimed he was not admitting murder but apologizing for leaving his son unattended in the car.

DeLeon also criticized James for not cooperating with the police in the investigation, but James testified that he had been advised by his defense attorney not to cooperate.

"Again I ask you, did you kill your baby?" defense attorney Robert Gutke asked his client.

"No, I did not."

During the 46 days between the reported kidnapping and Oct. 11, l986, when the baby's body was found, James' relationship with DeLeon was warm, he testified. However, their relationship became strained from the day the baby's body was found.

Angry with the police for failing to investigate other suspects, James testified that he owed De-Leon's brother-in-law, Manlio Te-peyec, $6,500 for cocaine _ a possible motive for murder.

James also admitted a prior felony conviction in California. Fifteen years ago, James was convicted of kidnapping a woman at gunpoint.

Other admissions included acknowledging that he had a child from a previous relationship _ but had no idea where the child now lives.

In cross-examination, prosecutors lambasted James for his last-minute alibi of a drug-related kidnapping.

"Never until this afternoon have you told anyone that you owed drug money," prosecutor Jenkins said.

James conceded that when police queried him _ at the time he reported the kidnapping _ specifically if drugs could be a motive, he denied any involvement with drugs.

In an angry voice, Jenkins continued to challenge James' kidnap scenario. "Isn't it the truth that the baby was not in the car . . . that the baby was already gone _ when you went into the store?" asked Jenkins.

James, obviously irritated with the questioning, denied the accusation.

The prosecutor argued that it was odd such a "loving" father would leave his child unattended in a hot car with the window only partially down _ and unlocked _ instead of carrying the baby with him inside an air-conditioned store.

Jenkins further criticized James for failing to contact the policeman who was near the "kidnapping scene." Instead of seeking the officer's help, James walked passed him and phoned 911 for emergency help, Jenkins said.

The prosecutor questioned James about differences between his testimony and statements made in earlier interviews with investigators. Jenkins said James never told police that the blanket the dead baby was found wrapped in had been stolen from his car. Yet James now says someone stole the blanket out of his car trunk _ a trunk that requires keys to open.

"Are you now suggesting the drop cloth (blanket) was in your car?"

"It's possible," replied James.

The prosecutor accused James of killing his child because he was jealous of the attention DeLeon gave her first-born and because James resented the burden the child added to an already financially stressed, unemployed new father.

James said the child was an added expense but not a burden.