Investigators dig up Long Island killings suspect Rex Heuermann's backyard with excavator

An excavator was seen over the weekend digging up the backyard of the home of the suspect in several killings on New York's Long Island and the heavy equipment was still behind Rex Heuermann's house Monday morning. According to law enforcement sources, investigators are looking into whether any victims may have been killed at the house, CBS News senior investigative producer Pat Milton reported last week.

Heuermann has been accused of killing three women and is the prime suspect in a fourth in the yearslong investigation into the Gilgo Beach killings. Heuermann pleaded not guilty to murder charges after he was arrested in New York City earlier this month.

Suffolk County Police Commissioner Rodney Harrison told reporters Monday that investigators are using ground-penetrating sonar at the house as well as cadaver dogs, CBS New York's Carolyn Gusoff reported. Harrison said numerous items have been taken from the house and the search of the property should be over in the next day or two.