Three people considered extremely dangerous are behind bars.

Police say they killed a young San Antonio man with a machete and then went on a drinking and shopping spree using the man's credit cards.

Robert White, 38, was arrested this weekend in Corpus Christi and put in the Bexar County Jail Monday.

U.S. Marshals say he is the one who led them to the couple they believe is responsible for the brutal murder of Christopher Duncan.

The body of the 23-year-old was found in a wooded area near Southeast Military earlier this month.

"We believe everybody in the public is in danger because of these folks," said U.S. Marshal Deputy Tom Smith.

They have now been identified as Thomas Ahrens and Kristi Tebo.

They were caught on surveillance tape buying a machete, camping equipment and clothes at Target and Wal-Mart on the Southeast Side.

At several stops they used Christopher Duncan's credit card.

"They just look like everyday, next door people, just a happy couple walking along," said Deputy Smith.

According to the affidavit, the couple and a third man, Robert White, met another person in Corpus Christi. They started hanging out and eventually Robert White told the man he had helped the couple murder someone in San Antonio.

That man got scared and went to police. Officers caught up to Robert White who gave them information about Thomas Ahrens and Kristi Tebo.

The couple was arrested in South Padre Island.

San Antonio Homicide Detectives are in the Valley interviewing the couple. They could be brought to San Antonio as early as Tuesday.