Scene of the accident on Interstate 10 near West Orange Grove Road. Faith Mascolino, 45, was in the back of a DPS cruiser and died when the vehicle was struck from behind by another car.

A manslaughter charge has been dismissed against a Tucson man who rammed a state trooper's patrol car, causing it to erupt into flames and killing a Marana mother of five.

Judge Richard Fields dismissed the case against Robert Gallivan, 30, at the request of prosecutors, who said there was "little substantial likelihood of a conviction."

Arizona Department of Public Safety officers pulled Faith Mascolino, 45, over in the early hours of June 3, 2009, on Interstate 10 near West Orange Grove Road. After conducting a sobriety test, they arrested her on suspicion of driving under the influence and placed her in the back of one of the officers' cruisers.

One of the officers was on the phone with Mascolino's daughter when the officers spotted a Nissan Altima coming toward them. The officers jumped over the guardrail and the Nissan crashed into the cruiser, which exploded and burned. Mascolino died and Gallivan suffered a broken ankle and a ruptured bowel, and at one point was put into a drug-induced coma.

"This has been a difficult situation for everyone involved. We appreciate the prosecution's thorough investigation and agree that a dismissal was the appropriate resolution," said defense attorney Dina Dieglio.

Dieglio's co-counsel, Michael Bloom said that as time went on it became clear Gallivan had committed no crime.

It took months for officials to wrap up their investigation; Gallivan was indicted 19 months after the crash, and that indictment was later struck down when Fields ruled prosecutors were unfair when they presented the case to grand jurors.

Grand jurors were told an accident reconstructionist thought Gallivan was going 112 to 116 mph in a 65 mph zone, but they weren't told that the DPS officers who jumped over the guardrail both think Gallivan was going between 60 and 70 mph.

Deputy Pima County Attorney Bruce Chalk held off on seeking a second indictment because of litigation and technical work involving Gallivan's telephone. Analysts were able to determine Gallivan was not speaking on the phone at the time of the crash, but it's unknown if he was texting.

Chalk told Fields last month he wanted permission to access Gallivan's texts, but Bloom told Fields their client no longer remembers his password. More important, they argued the state had no probable cause to believe Gallivan was texting and thus wasn't entitled to search his phone.

After Fields asked for the attorneys to write briefs on the issue, Chalk announced he would simply seek a new indictment without the text information.

After that, Chalk met with a panel of other veteran prosecutors who collectively decided the case should be dismissed, Bloom said.

Bloom attributed the prosecutors' decision to the fact that his client wasn't speeding and wasn't under the influence of alcohol or drugs. In addition, Bloom said experts were willing to testify at both Gallivan's criminal and civil trials that DPS troopers erred in where they pulled Mascolino over.

In a claim filed on behalf of the Mascolino family against Gallivan and the state of Arizona, the attorneys said DPS officers are taught not to stop where there is little shoulder space or at the crest of a hill.

The officers could have moved their cruisers and Mascolino to a safer area of I-10, and they could have put her in the first cruiser and not the last one, which is known in law-enforcement circles as "a target," the claim said.

The officers also could have gotten Mascolino out of the car as soon as they saw the Nissan approaching, the claim said.

Ronald Mercaldo, who represents Mascolino's family in the civil case, said the family always understood the criminal case against Gallivan was not a strong one.

The civil case was on hold because of the criminal case, but now that it has been dismissed Gallivan can be deposed and the civil case can move forward, Mercaldo said.

Contact reporter Kim Smith at kimsmith@azstarnet.com or 573-4241.