DECATUR - A police investigator says Amanda Hamm told him she knew her then-boyfriend was going to kill her children, but the tactics used to get that statement came under fire Thursday at her murder trial.

Hamm is accused of nine counts of first-degree murder in the Sept. 2, 2003, deaths of Christopher Hamm, 6, Austin Brown, 3, and Kyleigh Hamm, 23 months. The children were in the back seat of Hamm's car when it rolled into Clinton Lake.

The driver of the car, Hamm's former boyfriend Maurice LaGrone Jr., was convicted of murder last April. He is expected to testify when Hamm's defense begins next week.

A state police investigator testified Thursday that Hamm told him she knew LaGrone had plans to harm the children as the couple drove to the lake with the children.

Sgt. Ben Halloran said Hamm told him, "I knew Maurice was planning an accident but I didn't know what kind."

Hamm reportedly told police she learned at the lake that her boyfriend planned to drive the car into the water. Hamm said she asked LaGrone for the chance to play with her children before he did it, Halloran said.

Skelton questioned Halloran about the methods used to obtain the statement while she was a psychiatric patient at St. Mary's Hospital in Decatur. Halloran also was asked if he recorded the more than seven hours police spent with Hamm at the hospital.

Halloran said a tape recorder was not taken into the hospital, but the issue of recording was discussed by Halloran and three other officers.

"I made the decision not to record that interview," said Halloran.

Halloran admitted he deliberately misled Hamm, telling her a security camera recorded the incident at the boat ramp.

"That was a lie, yes," Halloran testified.

The jury was shown a video of a Sept. 10, 2003, interview of Hamm by Halloran and two female state police investigators. Hamm was allowed to leave the courtroom midway through the 45-minute video after she became upset.

The detectives told Hamm throughout the interview that they did not believe her assertions that the car went into the lake accidentally.

"You have three dead babies and you're telling me nobody made a decision," one female investigator told Hamm.

Hamm's response to police questions about how the car went into the water was, "I honestly have no idea." She cried and became hysterical during the interview.