GROESBECK, Texas (FOX 44/KWKT) – UPDATE: Authorities are trying to negotiate a peaceful ending to a standoff in the back parking lot of the Limestone Medical Center in Groesbeck.

Limestone County Sheriff’s deputies got a call about a man sitting in a vehicle there with a gun around 1:30 p.m., Thursday afternoon. That triggered a lockdown of the medical center.

Representatives from the center told FOX 44 News the lockdown started around 2 p.m. The sheriff’s office says the center is now open, but only for emergency calls.

The Limestone County Sheriff’s Office is working with the Groesbeck Police Department, and Texas Rangers.

Groesbeck ISD announced Thursday afternoon that campuses were placed on “Secure” status at 2:20 p.m. because of the standoff. That meant students would not be allowed to leave.

At 3:22 p.m., authorities told Superintendent Anthony Figueroa it was safe to release students.

At this time, authorities are not confirming what sparked the standoff.

As of Friday morning, the Limestone County Sheriff’s Office says the scene at Limestone Medical Center remains active. The 600-700 blocks of McClintic Drive remain closed to through traffic and non-essential personnel. Travelers should seek alternative routes until the situation is resolved.

Texas DPS shared on Friday morning that the man reportedly involved in the standoff has been identified as Adam Lenamond, a man found guilty of continuous sexual assault of a child.

This is a developing story. FOX 44 News will have more information as it becomes available.