A missing persons case turned to a murder investigation after the gruesome discovery of a Texas woman's body in a highway ditch.

Sabrina Tolentino Pina, 27, was apparently shot and killed after disappearing while running errands Saturday in the Houston area, police said. Her purse is missing.

"I can confirm that she was shot," Sgt. Wayne Kuhlman of the Harris County sheriff's homicide division told reporters Tuesday. "We’re not listing anybody as a suspect right now."

Pina was last seen in the parking lot of a Kohl's convenience store on Tomball Parkway at about 2 p.m., after taking a trip to a local Starbucks earlier that morning with her husband.

The Harris County Sheriff's Office positively identified the clothed body found Sunday morning as Pina. The medical examiner's office hasn't released a cause of death.

Family and friends had already planned a candlelight church vigil for Pina, an employee of TXU Energy, Monday night. It turned into a memorial service after the tragic discovery.

"It's like someone took my heart and broke it in half, to tell you the truth," Ivan Wilson, a longtime friend of Pina's, said at the service attended by about 800. "It's something you'll never get over."

Family friend Dr. Byron Holt described the University of Texas biochemistry graduate as "very bright."

"Now she's been taken off this earth for no good reason," Holt said at the memorial.

In a press conference held Tuesday, police said they had no motive and are asking for the public's help in solving the case.

They specifically want to know whether anyone saw anything out of the ordinary at the Kohl's parking lot where Pina was last tracked. Her father found his daughter's car there Saturday night, filled with shopping bags, according to MyFOXHouston.com.

Detectives believe that something happened to the young woman about 2 p.m. on Saturday. Her bank card and credit card transactions stop just before that time, they said. They're also analyzing footage from area stores' surveillance cameras. Pina was seen on video at a Sonic near the Kohl's about 1:30 p.m.

Loved ones began to worry about the young woman when she didn't show up for a family function Saturday evening. They say they don't know anyone who would want to hurt her.

"If you did this, be afraid, because good will prevail no matter what," Pina's best friend Tatiana Armenta told reporters Tuesday through tears.

Pina's family was too distraught to talk to the media, police said.

They have offered a reward of $30,000 for tips leading to Pina's killer. Anyone with information is asked to call CrimeStoppers at (713) 222-TIPS.

Click here for more on this story from MyFOXHouston.com.

Click here for more on this story from the Houston Chronicle.