On Wednesday, the supreme court stripped Castillo of his immunity from prosecution.
He leaves Congress this month to become mayor of Jutiapa, the town where Gutierrez was arrested in a region police say is dominated by drug smugglers.
Neither Castillo, nor his lawyers were available to comment on the arrest warrant.
Telephone calls traced
Gutierrez was arrested on Friday after investigators traced more than 60 telephone calls between him and the suspected killers, Matus told reporters.
Shortly after the bodies were found, four Guatemalan policemen were arrested after being tracked to the scene by a satellite positioning system in their car.
The policemen were then murdered inside a maximum security prison.
Investigators had said they knew the identity of "Montana 3," a code name used by Gutierrez during his phone calls with the suspected killers, but did not publicly identify him or detain him until now.
"Montana 3" had several telephone conversations with Castillo, according to investigators.
"He will be transferred to the capital under heavy security," Matus said.