Dawn Holland claimed Lohan flew into a rage after she was caught breaking her curfew, and also alleged the actress had been drinking.
She was later fired for talking about the incident to the press and subsequently withdrew her battery complaint against the "Mean Girls" actress.
However, the police investigation into the allegations continued and on the same day as Lohan's release, Palm Desert police sergeants Joe Borja and David Florez released a statement suggesting their probe concluded Lohan broke the rules of her probation.
They also revealed they were preparing to hand their findings to the local district attorney and the Los Angeles Probation Office for review.
The troubled star's lawyer, Shawn Chapman Holley, has expressed her dismay at the officers' decision to step outside their "limited role" and act as press representatives.
Holland tells People.com, "The important, yet limited, investigatory role of the police to gather facts and collect evidence is well-established. The fact that the Palm Desert Police Department went outside this limited role to issue a press statement expressing its opinion about what should happen in Ms. Lohan's case is highly unusual and deeply troubling."
Lohan spent three months in rehab to fulfill court-ordered treatment for violating her probation relating to a 2007 DUI conviction. She faces the prospect of returning to jail if officials rule she has breached the conditions of her probation again.