MALDEN — Omar Wilfredo Reyes had a bad feeling when he received a text from an alleged member of the vicious MS-13 gang last month, insisting they meet late one night.

But if he didn’t go, Reyes told his girlfriend, “They were going to beat him up,’’ a prosecutor said Monday.

Despite his misgivings, Reyes left his girlfriend’s apartment on Jan. 2. Roughly two hours later, the 19-year-oldwas found shot in the head on a bicycle path underneath a bridge in Everett. He died two days later.

Two 17-year-olds, Jose Vasquez Ardon and Cristian Nunez-Flores, both of Everett, are charged with murdering Reyes, also of Everett.At their arraignments Monday in Malden District Court,they pleaded not guilty. Both were ordered held without bail.

Both teenagers, who were arrested Saturday,are believed to be affiliated with the international street gang MS-13, Assistant District Attorney Carrie Spiros told the court. Authorities are searching for a third suspect in the murder.

“This case remains an open and very active investigation with a third party still unidentified as a participant in this murder,’’ Spiros said.

On Friday, dozens of members of the notorious gang were indicted on charges of murder, drug-trafficking, and other crimes. The arrests were linked to five murders, including the deaths of three teenagers in East Boston.

Reyes was with his girlfriend at her Everettapartment when Ardon sent him a series of text messages and “essentially lured the victim out of that apartment,’’ Spiros said.

“Mr. Reyes told his girlfriend that he had a ‘bad vibe’ about meeting up with Mr. Ardon,’’ she said.

But Reyes did so anyway, and met Ardon at 10:30 p.m, Spiros said. Reyes’s girlfriend tried contacting him 20 minutes later, but to no avail. She then called Ardon, who told her the two never met, Spiros said.

Police found Reyes bleeding on the path shortly after midnight on Jan.3, Spiros said. He died at Massachusetts General Hospital the following day.

Investigators located several surveillance videos that show Reyes walking toward the bike path with the three suspects, and another that captured Ardon and Nunez-Flores walking away from where Reyes was later found, Spiros said.

Two people identified Ardon as one of the people in the video.

Spiros said a witness told investigators that Ardon said he shot Reyes in the head and told another person that he was present at the time of the murder, alongwith two other men. Another person told investigators that Nunez-Flores said he was there, but thatArdon was the shooter.

Phone records revealed that Ardon and Nunez-Flores called each other on Jan. 3, the morning after the shooting, and thereafter.

The three alleged assailants fled to Ardon’s home and hid their clothes in the basement, Spiros said. Police recovered bloody paper towels froma trashcan at the home, along with the clothes. They were sent to a lab for testing.

Ardon’s DNA was found on a sweatshirt that matched the one he was seen wearing in the surveillance video, Spiros said.

As an interpreter translated statements made by the prosecutor,the baby-faced teenagers stood in the prisoner’s docket. Ardon appeared visibly uncomfortable, continuously biting his lip.

Ardon’s attorney, Kevin Mitchell, and his relatives declined comment after the hearing.

Edward Hayden, who represented Nunez-Flores, said the teenager moved to Massachusetts from his native El Salvador a year and a half ago. Hayden said the teenager’s parents remain in El Salvador.

Hayden said he had not spoken to Nunez-Flores about any possible ties to MS-13 and was unable to comment about it.

“He is a frightened teenager right now,’’ he said. “Of course, I’m concerned for his safety, as well as how this trial is going to play out, but I saw him yesterday in [the Department of Youth Services] and he was in a safe environment.’’

The two are due back in court on March 1.

Reyes’ relatives could not be reached for comment.A man suspected to be a relative of the victim was escorted away from the courthouse by police after the hearing.

Last month, another MS-13 member shot two people at the Maverick T Station, according to a law enforcement official with knowledge of the investigation.

An arrest warrant was issued a week ago for 21-year-old Rogelio Alvarado after police say he allegedly shot two men, ages 29 and 43, on Jan.19.

Alvarado had gotten into an argument with the younger man on an inbound Blue Line Train, MBTA police officials said.

The law enforcement official, who spoke on condition of anonymity because the person was unauthorized to speak on the matter, said Alvarado boarded the train at Airport Station when he spotted the 29-year-old, who is a member of the rival 18th Street gang. The older man was an former member of the same gang, and was shot when he came to the younger man’s aid, the official said.

Jan Ransom can be reached at jan.ransom@globe.com. Follow her on Twitter @Jan_Ransom.