WASHINGTON — Lloyd Welch, the main suspect in the Lyon sisters case, told police he believed the girls were “abducted, raped and burned up,” according to newly released court documents.

Welch is charged with two counts of first-degree murder in the disappearance of Sheila and Katherine Lyon. The girls were last seen in a Wheaton mall in 1975.

Welch made the disturbing comments during a conversation with investigators who have been interviewing Welch and his family since 2013. The Washington Post says that Welch has claimed in a letter to them that police were twisting his words, saying he had nothing to do with what happened to the Lyon sisters.

He has told investigators different stories at different times, the Post reports. Welch, they say, also told detectives that he saw the Lyon sisters at the mall, and also said that one of his uncles, Richard Welch, engaged in sexual activity with one of the sisters in his Hyattsville, Maryland, home. Richard Welch’s daughter, Patricia Ann Welch, tells the Post Lloyd Welch is “a pathological liar.”

The court documents also reveal statements made by one of Lloyd Welch’s cousins, Henry Parker, who said the family knew Welch was involved in the girls’ disappearance.

According to the documents, Parker told investigators that family members talked back in 1975 about Welch running away with two girls, trying to elude police.

Welch is a convicted sex offender currently serving time in a Delaware prison.