The ex-boyfriend of a missing pregnant woman has been arrested and charged with the murder of the woman and her 7-year-old son, whose bodies were found Tuesday, police said.

The bodies of Lisa Underwood, seven months pregnant, and her son, Jayden, were found near Denton, about 30 miles northeast of Fort Worth, where Underwood's sport utility vehicle was found Monday. Fort Worth police Lt. Gene Jones said authorities would provide more details at a news conference.

Underwood, a bagel shop owner, and her son were reported missing after she failed to show up at her baby shower Saturday. A pool of blood was found in her home.

Stephen Barbee, 37, of Fort Worth, was arrested Monday night in Tyler and was being brought back to Tarrant County by Fort Worth police. His bail was set at $2 million.

On Monday, Underwood's sport utility vehicle was found partially submerged in a creek near Denton.

Acting on an anonymous tip, police searched a Fort Worth home during the night and found an item referred to by the tipster, but officials would not say what it was or how it figured in their investigation.

Jones said he didn't know why Barbee was in Tyler, how investigators knew to find him there or whether there were other suspects.

"We haven't established a motive, so I can't speak to that," Jones said.

"We know that at one time Mr. Barbee and Ms. Underwood were romantically involved. We don't know what the latest status of that relationship was," he said.

Jones said he didn't know who was the father of Underwood's fetus, but a neighbor of Underwood, Debbie Lindley, said it was Barbee.

Lindley said Underwood and Barbee split up last the fall because Barbee had another girlfriend, but she didn't know of any violent incidents between the couple.

Lindley said Underwood met Barbee about two years ago at the bagel shop. She said Jayden had never met Barbee; the boy always stayed at the Lindleys' home when the couple went on dates.