Updated

Investigators on Thursday searched a farm owned by the family of Cosmo DiNardo, the man who confessed last week to killing four teens -- and who has claimed killing others.

Police vehicles and K-9 units were seen at the cornfield owned by the family in Solebury Township, located roughly 40 miles outside Philadelphia, FOX 29 reported.

DiNardo Cornfield

The Philadelphia Police Department and its K-9 Unit conducted a search of the Cosmo DiNardo's family farm in Solebury Township. (FOX 29 Philadelphia)

The 90-acre property was the scene of a multi-day search for Dean Finocchiaro, 19, Mark Sturgis, 22, Tom Meo, 21, and Jimi Taro Patrick, 19. After killing the four men, DiNardo said he burned the bodies in a metal tank that was converted into a cooker that he labeled a "pig roaster.”

During DiNardo’s confession last Thursday, the 20-year-old also said he had killed two people in Philadelphia when he was 15, a person with knowledge of the conversation told The New York Times.

A spokesperson for the Philadelphia police told FOX 29 homicide investigators are aware DiNardo made statements regarding killings in the city, and are attempting to determine if there is a link between the claims and any unsolved cases, but have few details.

PENNSYLVANIA MURDERS: KILLER USED PIG ROASTER TO BURN BODIES, OFFICIAL SAYS

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A law enforcement official escorts Cosmo DiNardo to a vehicle. (AP)

In an interview Tuesday with the Associated Press, Philadelphia's police commissioner called the information "sketchy," and added detectives have not yet had a chance to question DiNardo.

"We have to talk to him directly in order to have a starting point," Commissioner Richard Ross told the AP. "Dealing with it third hand is virtually impossible."

Bucks County District Attorney Matthew Weintraub is vetting all statements made by DiNardo in his confession, FOX 29 reported.

DiNardo has been charged with all four homicides and 20 other counts, including abuse of corpse, conspiracy and robbery, according to court documents. His 20-year-old cousin, Sean Kratz, is charged in three of the killings.

PENNSYLVANIA MURDERS: COSMO DINARDO'S STRING OF CONFESSIONS UNDER SCRUTINY

DiNardo and Kratz are being held in jail without bail. They are set to appear before a judge for a preliminary hearing in the case on Sept. 7, Bucks County prosecutors said.

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Bucks County District Attorney Matthew Weintraub holds up photos of four men during a news conference in Solebury Township, Pa. (AP)

DiNardo's lawyers say he is remorseful, and DiNardo told reporters last week he was "sorry."

Attorney Abby Leeds, retained Tuesday to represent Kratz, said on Twitter her client is charged with very grave crimes he and his family take very seriously. She vowed a "vigorous and dedicated defense."

"The Kratz family sympathizes with the families of the victims in this case," she said.

Read more from FOX 29. 

The Associated Press contributed to this report.