Vu told police how he killed her, but officials said they are going to wait for autopsy results.
After questioning him at length on Wednesday, police said they were confident of the motive.
"He was obsessed with their relationship," Waters said.
Police said the missing girl had apparently met someone else, however. Vu grabbed her while she was going to visit her new boyfriend, officials said.
"He stopped her and said, 'We need to talk.' She said, 'I'm done talking,' " Waters said.
Police said he killed her soon after that and took her body to the bayou.
Vu also admitted creating a bogus ransom demand that was sent in a text message to her family, police said. He demanded $50,000 and said they had two weeks to pay.
"He sent the note to deflect what had happened to her," Waters said.
Vu was among the friends and family members who were questioned Tuesday. Waters said he nearly confessed at that time. He refrained because he had heard in his native Vietnam that American police officers were skilled at catching criminals, the detective said.
"He wanted to see if that was so," Waters said. "He came down today (Wednesday) because he wanted to further the test."
http://www.chron.com/news/houston-t...g-teen-found-boyfriend-in-custody-5165636.php
