LOWELL — Three federal lawsuits filed by men who claim the city and a former vice detective failed to ensure that an informant wasn’t planting drug evidence will proceed toward trial after a judge denied motions seeking to throw the cases out.

Jonathan Santiago, Nel Sothy, and Mihran Mosko are suing both the City of Lowell and Officer Thomas Lafferty, a former Vice detective, for allegedly violating their constitutional rights by failing to adequately vet informants.

All three men were arrested on drug charges as a result of tips provided by a confidential informant who prosecutors later determined was not reliable.

The controversy arose in 2012 when an informant for Lowell police went to state police and claimed that another Lowell police informant was planting evidence.

An investigation into the informant who was allegedly planting evidence, conducted by the Middlesex and Essex district attorneys offices, led to 17 criminal cases being thrown out.

The investigation nevertheless determined that detectives “did not engage in any criminal wrongdoing or negligence in the performance of their duties.” The investigation also found no evidence that detectives “knew or should have known of their misconduct.”

Lafferty is a 20-year veteran of the department who was awarded an exceptional service bar in 2011, and a distinguished unit action bar in 2012 for his work with the Vice Unit. He was voluntarily reassigned from the Vice Unit to a patrol position after the controversy arose.

The city and Lafferty filed motions for summary judgment in the cases, claiming immunity.

U.S. District Court Judge Indira Talwani considered all three cases and the motions together. The cases were consolidated for discovery because they share similar facts and involve the same informant.

In making her ruling, Talwani reviewed evidence in the case in the light most favorable to the plaintiffs, because the defendants were moving for summary judgment.

Summary judgment is available in cases where a judge determines the plaintiffs cannot prove their case even when the evidence is considered in the light most favorable to them.

City Solicitor Christine O’Connor declined to comment on the ruling since the cases are still pending, but did say the city does not intend to file a pretrial appeal. Police Superintendent William Taylor also declined comment.

Lafferty is being represented by an attorney for the patrolmen’s union. Union President Francisco Maldonado did not respond to requests for comment.

Attorney Howard Friedman, representing all three plaintiffs, said the ruling speaks for itself.

“It essentially says we have enough evidence to go to trial,” Friedman said.

The informant, referred to as “FA,” in the ruling, is a known drug dealer who first began working with Lowell police as an informant in 2001 and 2002, according to the ruling.

In 2003, the informant was involved with the arrest of a man who claimed the cocaine he was caught with had been planted. That man’s case ended with a hung jury.

In 2005, the informant was arrested for allegedly trafficking cocaine. About the same time, then-Vice Unit commander Sgt. James Trudel determined the informant was unreliable, though that determination was not documented in the Police Department’s informants file, according to the ruling.

In 2006, Assistant District Attorney Thomas O’Reilly also came to believe the informant was unreliable, according to the ruling.

In 2008, the informant was arrested on charges he assaulted an officer. When his attorney reached out to Lowell police Lafferty told his supervisor, Lt. James Hodgdon, that the informant was reliable, according to the ruling.

In 2009, other Vice Unit detectives made controlled buys of drugs from the informant, but Lafferty continued to use the informant’s information, according to the ruling.

All three men now suing were arrested in 2012. Police found cocaine in locations where the informant told Lafferty it would be found. In two cases the informant had interacted with the men a short time before their arrests. In all three cases, the cocaine was determined to be of low purity.

Talwani denied Lafferty’s motion for summary judgment and claim to qualified immunity. She ruled a jury could reasonably conclude that Lafferty disregarded a known risk of evidence fabrication and arrested defendants despite that risk.

“Plaintiffs’ evidence, if believed by a jury, may show Defendant Lafferty’s reckless indifference to evidence planting, or at least a wholesale failure to weigh the reliability of the information to provided to him,” Talwani wrote.

Talwani noted in her ruling that a jury could reasonably conclude otherwise as well.

“But at this juncture, the record is such that a jury is entitled to draw it’s own conclusions, precluding summary judgment,” Talwani wrote.

Mosko also sued Capt. Barry Golner, a lieutenant in charge of the Vice Unit at the time of Mosko’s arrest and approved a search of Mosko’s vehicle.

Talwani did grant summary judgment to Golner.

“In contrast to the evidence as to defendant Lafferty, the record includes little to show that Defendant Golner willfully turned a blind eye to FA’s potential fabrications, or had direct knowledge of Defendant Lafferty’s unjustified reliance on FA’s tips,” Talwani wrote.

Talwani found that a jury could reasonably conclude that the city showed deliberate indifference to obvious consequences when it enacted a policy to supervise informants, but then failed to enforce the policy.

The judge found that Kenneth Lavallee, police superintendent at the time, was potentially aware that the policy wasn’t being enforced.

“In addition, the cavalier or simply non-existent enforcement of safeguards meant to protect against risks inherent to confidential informants, as described by Plaintiffs, may have been so extensive that a jury could conclude it occurred with Superintendent Lavallee’s blessing,” Talwani wrote.

Lavallee took issue with the judge’s characterization when contacted for comment.

“Any assertion that a policy wasn’t being enforced and that I was aware of that is completely untrue,” Lavallee said. “It would be my steadfast position that policies would be enforced in the Lowell Police Department and no policy would go unenforced with my knowledge. Any assertion to the contrary, I believe, is pure supposition on the part of the judge.”

All three cases are scheduled for a pretrial hearing on Tuesday.

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