The shooting at a San Bernardino elementary school that took the lives of three people, including the shooter, and critically wounded another, was the result of a domestic situation turned violent in a city that had not recovered from another bloody incident that took place 15 months ago.

But just weeks ago, nobody could have imagined that the marriage between Karen Smith and Cedric Anderson, both 53, would end so tragically.

The two married in January, but had known each other for about four years. He was a pastor with a military background, according to the Los Angeles Times. She was known as a caring teacher who had a special interest in children with learning disabilities. In Facebook posts, the two seemed to be happy as Anderson doted on Smith, calling her an “angel.”

But Anderson also had a past that included a history of weapons, domestic violence and possible drug charges that predated the marriage, the Associated Press reported. He was charged in Los Angeles County Superior Court with assault and battery, brandishing a firearm and disturbing the peace. But those charges were dismissed in May 2014.

Although they seemed to be a happy newlywed couple, something took place within the home that spurred Smith to leave Anderson about a month and a half into their marriage. But it is unclear exactly what happened.

“She thought she had a wonderful husband, but she found out he was not wonderful at all,” Smith’s mother, Irma Sykes told the L.A. Times. “He had other motives. She left him and that’s where the trouble began.”

Still, there were at least no outward signs of domestic issues that would lead to what happened Monday afternoon, police say. “No one has come forward to say they saw this coming,” police Chief Jarrod Burguan said.

Anderson was known by school staffers and he followed proper protocols to get into the building, saying he had to drop something off for his wife. He entered the special needs classroom where Smith was teaching 15 students and without saying a word, opened fire at her and hitting two other students behind her. He then turned the gun on himself. Both were dead at the scene. One of the children, identified as Jonathan Martinez, 8, was airlifted to a hospital where he later died. Another child whose identity was not released was hospitalized in stable condition Monday night.

The scene turned into one of chaos and panic, with parents hearing of the shooting rushing to the school, seeking their children but unable to connect with them. Holly Penalber, whose 9-year-old son and 7-year-old daughter attend the school, called it “every parent’s worst nightmare.” She said the long wait was “frustrating but also understandable.”

The 600 other students at the school were bused to safety at California State University’s San Bernardino campus, several miles away, after many walked off campus hand-in-hand, escorted by police.

Police say they are still trying to piece together what happened to cause Anderson to attack his wife and how security broke down in a school whose security was described as “very, very tight.”

“Once the school bell rings, the only way into the campus is through the front office,” said Maria Garcia, a San Bernardino schools spokesperson.

The shooting comes at a time when San Bernardino is still trying to heal from a mass murder that took the lives of 14 people and injured 22 in December 2015. The terror attack at a meeting of county employees ended in a shootout with police that killed husband-and-wife shooters Syed Rizwan Farook and Tashfeen Malik.

An overflow crowd gathered at sunset at Our Lady of the Assumption Church in San Bernardino to mourn and pray for the victims and survivors of Monday’s shooting. One man wore a shirt that read “stop the violence in SB.”

“Sometimes all we can do is cry. And today is the day for that,” Bishop Gerald R. Barnes told the gathering. “We’ll get up again. We’ll move on. We’ll become stronger. But today is the day to cry.”