Murder suspect Chander "Bobby" Matta told authorities he used a choke hold he learned at a Vermont military college to kill three prostitutes, an Arlington police detective testified yesterday.

During a preliminary hearing on one of the slayings, Detective Stephen R. Carter said that on the day Matta was arrested, he described to investigators how he killed Sherry K. Larman and two other women police have identified as prostitutes.

Carter said Matta, 21, picked up Larman May 25 near 13th and O streets NW in the District, and they drove to the home of Matta's parents in South Arlington, where they had sex.

As Larman, 26, was dressing in a bathroom, Carter said, Matta came up behind her, grabbed her around the neck with his right arm and punched her in the kidney with his left. With Larman on the floor, Carter said, Matta tied a plastic bag around her head and suffocated her.

"He said he didn't know why he did it . . . and that he didn't mean to do it," Carter said. "He said {the choke hold} was something he learned at military school."

Matta attended the Military College of Vermont in Northfield for one year. Officials at the 1,500-student college would not comment yesterday on Carter's statements.

As Carter spoke, Sandra Johnson, Larman's mother, clenched a tissue and shook her head as her eyes filled with tears. Larman's sister, Whitney, 24, bit her lower lip and stared at Matta, sitting at the defense table a few feet away.

When Carter described the discovery of Larman's body at a parking garage near Columbia Pike, Johnson and her daughter broke down, and were comforted by friends.

"It's so hard hearing how someone methodically killed your daughter," Johnson said later. "But I had to come. I had to see {Matta} face to face."

A few rows behind Larman's family and friends, several members of Matta's family, including his father, Jagjit, sat pensively throughout the hearing. They would not comment.

Matta, who appeared in blue jail fatigues and black tennis shoes, bowed his head as Carter described Matta's taped statements to police concerning the slayings of Larman, Jodie Marie Phillips, 16, and Sandra Rene Johnson, 20. All were killed by suffocation within 36 hours on Memorial Day weekend.

Matta has been indicted for murder in the deaths of Phillips and Johnson. At the conclusion of yesterday's hearing, General District Court Judge Joseph C. Gwaltney referred the Larman case to a grand jury, which will consider another indictment against Matta.

Yesterday's hearing, although preliminary, offered a glimpse of some strategies that Matta's lawyers could use in what may be three murder trials this fall.

Matta attorney Arthur M. Reynolds Jr. said yesterday he will file several motions by Friday, including one asking that most statements Matta made to police on the day of his arrest, June 10, be ruled inadmissible as evidence.

During yesterday's hearing, Reynolds asked Carter why a statement Matta signed acknowledging he understood his right not to incriminate himself and his right to an attorney was not completed until about four hours after Matta had been talking to police.

Shortly after Matta signed the statement, Carter said, Matta "broke down," and made statements that police interpreted as confessions to the three killings.

"He was in the hands of police, who are experts at psychological oppression, without an attorney," Reynolds said.

Although Matta has not been indicted in the Larman slaying, Arlington prosecutors tentatively have scheduled a Nov. 28 trial date. Matta is to go on trial in the Phillips slaying on Oct. 22, and on Nov. 13 in Johnson's death.