Brock Turner's parents are scared for their son's safety ... so much so they've asked cops to help them deal with protesters and others who might do him harm ... TMZ has learned.
Law enforcement sources in Ohio also tell us ... they're tracking social media to monitor any threatening activity -- whether it be from Sugarcreek Township residents -- many of whom are unhappy about a sex offender in their 'hood -- to angry outsiders.
Law enforcement is vague about actual threats, but one source did say, "Everybody is always concerned about death threats."
Protesters are expected in force over the weekend at the Turners' house. One protester tells us some of them will be open carrying, but he vows to refrain from violence.
Brock was released from jail Friday morning after serving 3 months for sexual assault. He'll have to register as a sex offender.