Discuss as:

Sketch released in shooting of teen lesbian couple

A sketch of the single suspect in the murder of Mollie Judith Olgin and the aggravated assault of Mary Kristene Chapa.

Police have released a sketch of a suspect in the shooting of a South Texas couple that left one dead and another wounded last month.

With help from a witness, Portland police described the alleged gunman as a skinny male in his 20s, weighing 140 pounds.  The sketch was released late Wednesday.

Mary Kristene Chapa, 18, and Mollie Judith Olgin, 19, were both found June 23 in a park with gunshot wounds to the head. Olgin died from her injuries and Chapa remains hospitalized. 

Teen lesbian couple found shot in Texas park

The two women were involved in a relationship, according to family and friends, though it's not clear if that was the motive for the shootings. So far, the incident has not been ruled a hate crime. 

The couple had planned to spend time in the park before going to see a movie. Olgin's family became worried when she didn't show up for work the following morning. 

Father of slain lesbian teen in Texas: 'Justice will be served'

Portland Police Chief Randy Wright told msnbc.com the shooting appears to be a random act, but the investigation is ongoing. 

Police recovered a bullet casing at the scene, but no weapon. Witnesses told police they heard what could have been gunshots or firecrackers the night before the girls were found, but they never reported it.

Chapa has not been formally interviewed by police because of her medical condition. 

Friends reel from shooting of teen lesbian couple in Texas

The Texas Rangers joined the investigation, which is being led by Portland police, after offering their assistance.

No one from the Portland Police Department was immediately available for comment. 

Shooting of two teenage girls shocks Texas community. KRIS reporter Lindsay Curtis has the story.

More content from msnbc.com and NBC News:

Follow US News on msnbc.com on Twitter and Facebook