Criminal charges are mounting against a suspected thief accused of stealing scrap metal and other property from two Butler County businesses.

David F. Marchinoski, 31, of Concord Township also forged thousands of dollars worth of stolen checks from a third business, state police said.

Investigators suspect Marchinoski had some familiarity with two of the businesses — he used to work there.

The defendant has been in the Butler County Prison since Jan. 21 when he was arrested for allegedly pilfering more than $40,000 worth of equipment from Standard Bent Glass in East Butler.

On March 20, troopers filed two new cases against him.

Marchinoski in the latest charges is accused of stealing scrap from Biofab Products in Summit Township and buying merchandise with forged checks belonging to Litzenberg Drilling in Concord Township. Police allege the suspect, with the help of his girlfriend, 28-year-old Tabitha E. Saye of Oakland Township, between Jan. 6 and 21 broke into Biofab, a metal fabricating firm less than two miles from Standard Bent Glass.

He took scrap valued at more than $2,000, according to court documents, while Saye allegedly acted as a lookout and getaway driver.

Investigators believe Marchinoski sold the stolen property at local scrap yards. He and Saye both face felony theft-related charges as well as trespass in the case.

District Judge Lewis Stoughton on Monday issued an arrest warrant for Saye.

Police also suspect Marchinoski between Dec. 29 and Jan. 6 forged five stolen checks from Litzenberg Drilling to buy items totaling $2,224, documents said.

Additionally, he allegedly made eight fraudulent purchases worth a combined $310 using gas cards belonging to the same company. He is charged in that case with felony counts of forgery, theft by deception and receiving stolen property.

Court papers noted that Marchinoski once worked at Litzenberg Drilling as well as at Standard Bent Glass.

While he briefly worked at the East Butler company, police said, the defendant allegedly took aluminum racks from an interior storage area during nonworking hours.

The racks, valued in excess of $40,000, are used in the processing of glass products at the plant, according to company officials.

Investigators eventually tracked the stolen racks to Bob’s Auto Salvage on Route 38 in Oakland Township, where Marchinoski sold them, documents said.

The defendant in that case is awaiting trial on charges of burglary, trespass and theft, all felonies.

He is being held in the county jail on $35,000 bail.