WATERBURY - Maryann Measles had just turned 13 when she started hanging around with a group of eight people in their late teens or early 20s. But she seemed older to some in the group.

"I thought she was 14 or 15," said Maggie Bennett , who testified Tuesday in the murder trial of onetime friend Keith Foster .

Measles knew two girls in the group and in September 1997 began hanging out with the older crowd more frequently, Bennett said. Bennett recalled visiting one of the girls' houses a few times a week and seeing Measles there. "I'd stop there to smoke (marijuana) with them," Bennett said.

The group of friends would also go to a secluded spot on River Road in New Milford to smoke pot, Bennett testified. Measles smoked with them there, too, Bennett said.

But drugs weren't the worst thing to happen to Maryann Measles. Authorities say the eight friends beat, raped and held Measles under water at the River Road site on Oct. 19, 1997. They eventually wrapped up her body and tossed it in the Housatonic River, authorities said. Nine months later, it was found in Lake Lillinonah. The five men and three men were arrested in 2002.

Six of them have pleaded guilty. Foster is the first to go to trial. Over the past seven weekdays, prosecutors have called five of Foster's former friends as witnesses, largely in an attempt to establish his role in the beating, rape and killing.

If convicted, Foster could face life in prison. But his lawyer has said Foster wasn't present at the killing.

On Tuesday afternoon, the prosecution's questioning of Bennett, 27, seemed to drive at the motive. Authorities said the eight friends were angry at Measles for going to police and making statutory rape claims against several of the men.

In the fall of '97, it seems many of the friends had paired off. Bennett said she was "sleeping with" A.J. Walter . Meanwhile, Foster was having a sexual relationship with Dorothy Hallas , and June Bates Seger was sexually involved with Jeffrey Boyette , Bennett testified.

Questioned by prosecutor David Shepack , Bennett said she learned in early October that Ron Rajock, Walter and Foster had slept with Maryann. "I was upset because (Walter) was my boyfriend at the time," Bennett said.

One week before the killing, Bennett said she heard from Dorothy Hallas that Measles' mother was pressing charges against Walter and Foster. "(Hallas) was upset also, as I was," Bennett testified. "Ron (Rajock) mentioned he was the next one to have charges brought against him."

When asked if Foster was aware that Measles went to police, Bennett replied that he was. Before she could answer another question defense lawyer Don O'Brien objected. Superior Court Judge Thomas O'Keefe said Bennett could address the topic, but he then adjourned court for the day.

Also Tuesday, A.J. Walter, who was described by authorities as the ringleader, finished testifying. He has said the group held Measles under water to try to scare her into dropping the police complaints. He said her death was an accident.

He put Foster at the scene of the killing, but flip-flopped on whether Foster helped hold Measles underwater. Prosecutors say that Walter once told police that Foster was in the water. But on Tuesday, Walter said that was not the case.

"That's not true?" O'Brien asked.

"No," Walter replied. "He was standing there without doing anything."

Later, Shepack asked: "Does (Foster) attempt to stop you in any fashion" from holding Measles underwater.

"No, he doesn't," Walter replied.

"Does he attempt to give her any first aid when she gets out of the water?" Shepack asked.

"That's a negative," Walter replied.

Still, Walter suggested that Foster is as "guilty as anyone else in this." Walter also said that Walter is not the only one who should be considered "a monster."