The person who stabbed to death a couple and their son may have injured his or her hand, arm or another body part, police said Wednesday in a new appeal for the public's help in solving the crime.

Also, the killer may have lied about his or her whereabouts from 1 to 3 a.m. Saturday, when Thomas and Lisa Haines and their teenage son Kevin were slain, Manheim Township police said.

"If you know this person, you may not think they are capable of this type of crime," police said in a news release. "They may also have fabricated an alibi concerning their whereabouts during this time frame. They may not have a prior record of violence."

Chief Neil J. Harkins said investigators are working on tips that have come in during the past few days. He previously said there were no suspects, but on Wednesday was less specific.

"The best I can tell you right now, the fair thing to say is we're still working on leads, promising leads," he said.

The Haineses' daughter, Maggie, went to her parents' bedroom after being awakened by noise around 2 a.m. Saturday, police said. Her father was lying on the bed and her mother was sitting on it.

Lisa Haines told her daughter, who had returned home from Bucknell University for the summer a day earlier, to seek help. She summoned police from a home across the street.

The couple and Kevin, a 16-year-old high school sophomore, were found dead inside the home. A back door was ajar and nothing appeared to have been taken.

The coroner said the victims' bodies have been released to Charles F. Snyder Jr. Funeral Home and Chapel Inc. in Lititz. A woman who answered the phone there Wednesday declined comment.

Detectives spent some time on Wednesday looking into a burglary that occurred overnight at a home north of Lititz, about seven miles from the scene of the killings. They concluded the two incidents were unrelated.