Police in three states might have prevented mass shootings over the weekend by arresting a 22-year-old man from Connecticut, a 25-year-old Floridian and a 20-year-old Ohio resident, all of whom had access to firearms and ammunition and threatened dangerous action, authorities said.

Two weeks after the massacres in El Paso, Texas, and Dayton, Ohio, which killed at least 31 people, law enforcement said these three young men had expressed hopes of joining the ranks of alleged gunmen Connor Betts and Patrick Crusius.

Like the three men, Betts and Crusius were recently out of school and either unemployed or intermittently employed — circumstances that often place the burden to spot a problem on those closest to the would-be shooter or, perhaps, a Good Samaritan who happens upon a social media post and reports it.

The result is that the difference between a mass shooting and an upended plan can often come down to chance, luck or a tipster. Over the weekend, several close calls were undercut this way, authorities said.

The FBI and police department in Norwalk, Conn., arrested Brandon Wagshol on Thursday after receiving a tip that he was looking to purchase ammunition out of state. Wagshol, authorities said, had boasted on Facebook about his fascination with committing a mass shooting and was building a do-it-yourself rifle with parts he purchased online.

A search of his home uncovered several weapons, including a handgun, a rifle, numerous rounds of ammunition, body armor, a ballistic helmet and other tactical gear, police said; the Associated Press reported that some of the firearms were registered to Wagshol's father.

'A good 100 kills'

Tristan Wix was arrested Friday after sending a series of text messages elaborating on a personal goal: to "break a world record for longest confirmed kill ever," according the Volusia County Sheriff's Office. The Daytona Beach, Fla., resident was stopped in a Winn-Dixie parking lot Friday and arrested, CNN reported, after his ex-girlfriend alerted local law enforcement about his threats of a mass shooting.

Wix — who told his girlfriend that he aimed to reach "a good 100 kills" — claimed in text messages to have selected the ideal shooting location, authorities said. Unlike a school, which he called a "weak target," his site would enable him "to open fire on a large crowd of people from over three miles away."

Although Wix initially told investigators he didn't own firearms, detectives recovered a .22-caliber hunting rifle and 400 rounds of ammunition from his apartment. Wix was charged with making written threats to kill and is being held without bond.

Outed on social media

On Saturday, James Reardon was arrested in New Middletown, Ohio, and charged with telecommunications harassment and aggravated menacing after threatening to shoot up a Jewish community center. The self-described white nationalist was outed to law enforcement via social media.

Reardon's Instagram account, riddled with anti-Semitic slurs, had one particularly alarming photo, which was brought to the police department's attention: a man shooting a rifle into the darkness, geotagged at the Jewish Community Center of Youngstown, Ohio, and with a caption that read, "Police identified the Youngstown Jewish Family Community shooter as local white nationalist Seamus O'Rearedon." (According to CNN, "Seamus" is a Gaelic version of Reardon's name.)

New Middletown Police Chief Vincent D'Egidio said that two assault rifles, rounds of ammunition, a gas mask, bulletproof armor and anti-Semitic propaganda were recovered from Reardon's home.

But the weekend arrests are just the three most recently foiled potential plots. Authorities in South Carolina arrested a teen last month for making threats after racist videos surfaced in which he fired a semiautomatic rifle at objects meant to portray black people and said he planned "to shoot up" his Catholic high school.

School officials learned of the videos from students' parents. The student was expelled and school officials called police, who arrested the teen.

The same week, a 19-year-old Texan called his grandmother and told her that he planned to "shoot up" a hotel with his AK-47 rifle and then commit "suicide by cop." She talked him out of it and took him to a hospital for evaluation; he was later arrested on federal firearms charges.

"We avoided another huge crisis," U.S. Attorney Erin Nealy Cox said last month, referring to a June shooting at the Dallas federal courthouse. The Texas teenager had not been on any state or federal watch list. Had his grandmother not stepped up, Cox said, "we wouldn't have known he was contemplating this. She saved his life, injury to him and probably multiple people's lives."

The South Carolina and Texas arrests came days before the mass shootings in El Paso and Dayton, highlighting some of the challenges law enforcement face in investigating and prosecuting cases of suspected domestic terrorism.