A defense attorney for Paul Leon Jordan, who is charged with murder in the deaths of a 3-year-old girl and her baby sitter, attempted yesterday to discredit a homicide detective who is a key prosecution witness. The attorney tried to paint the detective as an officer who ignored police procedures, built up emotional pressure on Jordan and then lied to get Jordan to confess to a crime that he did not commit.

Detective Joseph Schwartz, who has testified that Jordan confessed both orally and on videotape to the slayings of the child and her 56-year-old baby sitter, acknowledged in D.C. Superior Court yesterday that he first built up emotional pressure on Jordan during a 2 1/2-hour interrogation by telling him that the child "couldn't go to heaven" until the truth about the slayings was known.

He also testified that he misled Jordan, who initially denied any involvement, by telling him, "I know you didn't mean to do it."

Schwartz, who conducted the long interrogation of Jordan Feb. 14, acknowledged that he had no information at the time that connected Jordan, a 48-year-old alcoholic, with the January slayings of Crystin Fletcher, the only child of two D.C. police officers, and Cora Barnes in Barnes' home at 4321 Second St. NW. Jordan has pleaded not guilty to the charges.

The defense has asserted that the videotape shows a man trembling, sweating and debilitated by alcohol withdrawal and that it contains numerous details about the crime that police knew were false.

Defense attorney James H. McComas attempted to show that Schwartz refused to accept Jordan's initial denials, and that Jordan confessed only to escape the mounting pressure of the interrogation, including Schwartz's comment that the child couldn't go to heaven until the truth was known.

"When you said [that], you didn't know Mr. Jordan and his first wife had lost a child in infancy, did you?" McComas asked. Schwartz responded, "No, I was talking about Crystin."

Under questioning by prosecutor Amy S. Berman, Schwartz said he continued questioning Jordan for hours because "the more we talked about the child, about being there the day of the murder . . . he had tears in his eyes, he began to shake. I believed he knew something about the murder."