An autopsy found bruises on Angara's neck consistent with choking, as well as on her waist and elbows, suggesting she had been involved in a violent struggle, but not a deadly one.

Investigators classified the case as a homicide, believing the killing had been intentional; they put Angara's death as having occurred the day before.

[4] Investigators have also considered the possibility that the death was purely accidental, based on the work of a Scottish pathologist who argues that injuries very similar to those associated with strangulation can occur as victims drown in very cold water such as that Angara was found in[5]—the theory is that the plate over the tank might negligently have been left open following some sample collection for water testing.

Struck by similarities with a 1968 killing of a woman, also in Passaic County, alone while in a high-security industrial complex on a weekend, they looked for leads in that case's file.

[6] In 2007, Angara's family, frustrated by the lack of progress, successfully pushed for the state's Attorney General to review the case, but that effort did not result in any new leads or information either.

[8] Angara married another Indian émigré who worked in banking,[2] and the couple shortly had the first of their three children, settling at first in Clifton, New Jersey, a suburb in Passaic County.

After a year at Merck analyzing compounds,[9] in 1992 Angara began working for the Passaic Valley Water Commission (PVWC),[8] a public utility owned by Clifton and the neighboring cities of Passaic and Paterson,[10] which provides 83 million US gal (310,000 m3) of water daily[3] to 800,000 customers in those cities and 14 other communities in that region of North Jersey.

[2] Seven years later, the family moved to Holmdel, 42 miles (68 km) to the south in Monmouth County, where they believed the school system was better.

The subordinate who had reminded her of the need to calibrate the instruments went into the basement, noticing broken glass on the floor in one area about 15 to 20 minutes later.

[2] Repeated calls to her cell phone from her family in Holmdel, where she was supposed to give her daughter a ride to an afternoon basketball game,[11] had gone unanswered.

[9] Workers searching the basement found an area where one of the 4-foot-wide (120 cm), 50-pound (23 kg) aluminum floor panels that opened onto the million-gallon (3,800 m3) tanks was slightly ajar, and the 12 screws which normally held it in place were broken or missing.

Before refilling the tanks and restoring service, the commission issued a boil-water order to customers as a precaution; this was lifted at the end of the following day.

Angara's body had been immersed for over a day, and the heavy chlorination in the water eliminated any trace evidence, such as DNA or fingerprints, that another person might have left on it or her clothing during the final struggle.

[12] Many firefighters and police officers, as well as plant workers, had walked through the putative crime scene before the body was found, leaving it severely compromised.

[9] Detectives found that many of her coworkers thought well of her, saying that in addition to being devoted to her work and cheerful, she was modest, asking them not to address her as "Doctor" and simply use her first name instead.

Her job responsibilities as senior chemist did not include hiring or firing authority, making it unlikely that a workplace dispute could have arisen from those possibilities.

[11] From the strength required to lift and replace the access panel, and struggle with the 5-foot-5-inch (165 cm), 175-pound (79 kg) chemist, police came to believe the killer was male[3] (although the county coroner argued that a woman in sufficient physical condition could have done those things as well).

"Either there is some very powerful motive out there that someone has kept completely to themselves, or it may suggest this wasn't a planned killing", such as a confrontation that got more heated, chief assistant prosecutor John Latoracca told The New York Times.

James Wood, chief homicide detective for the prosecutor's office, told The New York Post, that another suspect was in his opinion about to confess before retaining counsel and refusing to speak with police further.

[2] After Angara's death, the PVWC contracted for improved security, including armed guards patrolling inside and outside the plant at all hours.

[14] Ten years after the killing, when the Angara family had lobbied state senator Joe Kyrillos to support their call for another state-level review, police suggested that they might have been mistaken about the three suspects.

"[W]e looked into the additional things that became areas of concern in interviewing these folks", chief assistant prosecutor Latoracca told The Star-Ledger, "and based on that, we thought that while there were reasons they came across as hinky, we ultimately didn't believe they actively killed her".

They had contacted Scottish forensic pathologist Derrick Pounder of the University of Dundee,[5] one of the few experts in the field of drownings,[4] particularly those that occur in cold water.

His research has found that in a small percentage of such cases, the victim experiences bruising on the neck and petechiae on the eyeballs that closely mimics injuries otherwise seen as strong indicators of premortem strangulation.

[5] Pounder never examined Angara's body (and could not have, since it had been cremated shortly after her death[17] in accordance with Hindu funerary traditions), nor any of the records from the autopsy.

By the time of the third anniversary of Angara's death, he had come to believe, in part after considering Pounder's research, that the case was an accident resulting from negligence rather than an act of malice.

[20] An unnamed plant worker told The New York Post that on the day of Angara's death, the state had ordered some testing as a result of the pinkish discoloration.

[15] At that time the county prosecutor's office described the case as "open but inactive"; chief assistant prosecutor Latoracca, who was by then in private practice as a criminal defense attorney, said he understood why Wood and some other detectives had come to believe Angara's death was an accident but reiterated that he had faith in the medical conclusions that her death had been caused intentionally.