Prosecutors say 19-year-old Ricky Gonzalez pleaded guilty Thursday to bank robbery and embezzlement of bank funds.
International Bank of Commerce was robbed March 23 by two masked, armed men.
Gonzalez is the boyfriend of 18-year-old Estefany Danelia Martinez, who was a teller. A tip led investigators to the Facebook site and the comment posted by Martinez.
Martinez, fellow teller 19-year-old Anna Margarita Rivera and Rivera's brother, 22-year-old Arturo Solano, previously pleaded guilty.
All four face maximum 10-year prison terms for bank robbery and 30 years for embezzlement, during sentencing later this year.
Investigators say about $62,000 was stolen. More than half of the money has been recovered.