FRAMINGHAM — Prosecutors dropped charges Thursday against four illegal immigrants from Guatemala who were accused of attacking a man and a woman at knifepoint this month, citing new evidence in the case that cast doubt on the allegations.

The new evidence included video footage and additional statements from witnesses, prosecutors said.

When the evidence emerged, prosecutors said they notified the lawyers for the four men and assigned the accusing couple lawyers to represent them. The couple then invoked their right against self-incrimination, forcing prosecutors to dismiss the case.

“The prosecution saw a problem with the witnesses’ stories, and brought it to our attention, as is their duty,’’ said John Daly, a lawyer for one of the men.

The couple’s names are redacted in police reports. They have not been charged.

The couple initially told police they were walking home from a store on March 13 when they encountered several men who were “intoxicated and stumbling,’’ according to court records.

At first, the woman told police that the men were friendly and offered her boyfriend a beer. But then, she said, one man propositioned her. When she refused, two of the men dragged her to a nearby apartment, sexually assaulted her and beat her boyfriend, she told police.

Her boyfriend told police that two of the men threatened them with knives and several threatened to kill them.

The men — Ariel Diaz, 24, Elmer Diaz, 19, Adan Diaz, 32, and Marlon Josue Jarquin-Felipe, 27, were originally charged a host of crimes, including rape, indecent assault and battery, assault with a dangerous weapon, and kidnapping. On Thursday, they all stood motionless as the charges were dropped.

According to federal immigration officials, Ariel Diaz has prior convictions for disorderly conduct and DUI from 2009. He and Jarquin-Felipe were previously deported and illegally reentered the United States at an unknown date.

Diaz was arrested again in December 2015 on another DUI charge. Adan Diaz was also arrested on drunken driving charges in February. The state plans to move forward in that case, prosecutors said in court.

Neither of the Diazes’ recent drunk driving case was reported to ICE, officials said.

Robert Costello, the defense attorney for Jarquin-Felipe, said he does not believe his client poses any danger.

“He had absolutely no record,’’ Costello said.

The men remained in custody after the hearing. A spokesman for the US Immigration and Customs Enforcement released a statement stating that federal officials intend to “assume custody of all four individuals.’’

Maria Sacchetti of the Globe staff contributed to this report. Astead W. Herndon can be reached at astead.herndon@ globe.com. Follow him on Twitter @AsteadWH