Texas Rangers have joined the investigation of a Southern Methodist University student reported missing last week and found dead in a portable toilet in Hewitt, Texas, police told FOXNews.com Thursday.

Meaghan Bosch, 21, was found Monday by a construction worker in a Port-a-Potty near Waco, Texas, about 100 miles south of Dallas. Her family reported her missing on May 11, a day after she was last seen at a Dallas-area grocery store.

"It's still an ongoing investigation. We classified it as a questionable death at this time," Capt. Tuck Saunders of the Hewitt Police Department told FOXNews.com. "We're gathering the facts and we'll see where the facts take us."

Toxicology reports were still pending with the Dallas County medical examiner, Saunders said.

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"That would help in our determination, knowing if there were or were not any narcotics in her system," he said.

Her family said she was last heard from Thursday afternoon when she sent her ex-boyfriend a text message saying she was at the home of a drug dealer.

After Bosch missed dinner with her boyfriend Thursday evening, he told her parents Friday that she never showed up, according to the family. Her parents then contacted Dallas police.

"She had sent a text message to a friend on the evening of May 10 and had gone to the grocery store and that was the last time anybody saw her or heard from her," Corp. Donna Hernandez of the Dallas Police Department told FOXNews.com.

Bosch's father told media that the family first learned of his daughter's cocaine use two months ago.

"A terrible crime has been committed against her, her family, and friends," her father, Joseph Bosch, said in a prepared statement Wednesday, the Dallas Morning News reported. "The police are working very hard on the case, and we are confident that they will bring the people responsible to justice."

Bosch's truck was found at her off-campus apartment. The vehicle was unlocked and the keys were inside, police said. Her family said her apartment was locked.

But Bosch may have made contact with friends via text messages through Saturday, said Lt. Robert Hinton, the commander of Dallas' missing persons squad.

"She was not alleging that she was in any criminal danger," Hinton told the Morning News.

Police said it appeared Bosch was placed in the portable toilet. Fingerprints had to be used to identify her decomposed body, the Morning News reported.

The Associated Press contributed to this report.

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