"We vehemently deny these allegations and, if charges are filed, we will fight them in court, not in the press," her attorney, Shawn Chapman Holley, said Saturday.
Kamofie & Co., a custom jewelry store in Venice, Calif., reported that the "one of a kind" necklace was stolen on Jan. 22. Lohan, 24, was released from court-ordered rehab at the Betty Ford Center three weeks prior.
Police obtained a search warrant Tuesday to try to get back the necklace from Lohan's house, but the item was turned in to detectives before the warrant could be executed.
Lohan — who is still on probation — was sent to jail twice last year for violating her probation, which stems back to a 2007 drunken driving case. Riverside County prosecutors are also considering charging Lohan with battery for a December altercation with a Betty Ford Center employee. She was ordered to go to rehab for three months after she admitted to failing a drug test in September.
Lohan is due in court Feb. 25 for a probation hearing.