Criminal charges were dropped against 57 people arrested during a pro-Palestinian demonstration at the University of Texas at Austin this week, according to the Travis County attorney’s office.

But the Texas Department of Public Safety said Friday that it is launching a criminal investigation into a journalist arrested at the protest.

Criminal trespass charges were filed against the arrestees, who were booked in Travis County Jail on Wednesday, sheriff's spokesperson Kristen Dark said. As of 5 p.m. Thursday, Dark said all arrestees had been released from custody.

A spokesperson for Travis County Attorney Delia Garza said Friday that law enforcement lacked probable cause in the 57 cases she dismissed. Probable cause is the reason law enforcement provides to justify arrests.