Authorities believe the gunman who killed 49 people at Orlando's Pulse nightclub conducted surveillance trips at both the club and a Disney entertainment and shopping complex this month, a law enforcement official said Tuesday.
Omar Mir Seddique Mateen's visits at Pulse and Disney Springs happened between June 1 and June 6, said the official, who has knowledge of the investigation. The number of visits to each venue was not specified.
In Southern California, Disneyland has been increasing security since December, a spokesperson told KTLA.
"Unfortunately we’ve all been living in a world of uncertainty, and we have been increasing our security measures across our properties for some time, adding such visible safeguards as magnetometers, additional canine units, and law enforcement officers on site, as well as less visible systems that employ state-of-the-art security technologies," the spokesperson said in a statement Tuesday.
Several Disney park-goers told KTLA they felt the increase security would make them feel safer.
The dates of Mateen's visit to the Florida park coincided with Gay Days 2016 celebrations taking place at Walt Disney World and other Orlando locations between May 31 and June 6.
Investigators believe the visits were intended to surveil the locations, based on information learned in interviews.
The visits also came in the same time period when Mateen was purchasing the weapons used in Sunday morning's nightclub attack.
The day before that rampage -- the deadliest mass shooting in U.S. history -- Mateen spent several hours at Disney Springs, formerly known as Downtown Disney, law enforcement officials said.
Authorities said they believe Mateen was alone at that time.
Earlier Disney visit with wife
Disney security officials have told the FBI they believe that Mateen made another visit to Disney World on April 26 to conduct reconnaissance, the law enforcement official said.
The FBI is investigating that possibility.
Investigators don't know whether Mateen's wife, who was with him on the Disney World visit, knew or suspected at the time about her husband's intent, the official said.
Items seized from homes
The FBI has seized documents from Mateen's home as well as items from the homes of his parents, sister and brother-in-law, the law enforcement official said.
The items included a Dell computer, a smartphone, a digital camera and related media.
Mateen's phone was recovered at Pulse. FBI Director James Comey would not say Tuesday whether authorities have accessed the phone.
To some, Mateen was angry and homophobic, reportedly spewing outrage at the sight of two gay men kissing.
But he was also a friendly and familiar face at the gay club he eventually terrorized, killing 49 people.
Chris Callen, who worked at Pulse as a performer, told CNN's Anderson Cooper he had seen Mateen dozens of times at the club. According to Callen's estimate, Mateen visited Pulse twice a month over a period of three years.
"He was very friendly when we said, 'Hi.' He didn't seem like the kind of guy who just did what he did. It makes no sense," Callen said.
"My partner said that he was very nice (and seemed) comfortable."
Pulse regular Kevin West told the Los Angeles Times that Mateen messaged him on a gay dating app several times in the year before the attack.
But that picture doesn't match up easily with accounts from colleagues who said Mateen was known to make anti-gay remarks frequently.
"He was an angry person, violent in nature, and a bigot to almost every class of person," former co-worker Dan Gilroy told CNN affiliate WPTV-TV in West Palm Beach. Mateen and Gilroy had worked together at PGA Village in Port St. Lucie
Gilroy said Mateen had a temper and often made homophobic, sexist and racist remarks.
"He would hit things and as he was hitting things, he would yell, and of course there was always curse words involved," Gilroy told the station. "And this wasn't seldom, this was all the time."
He said he wished he could have done something to prevent the tragedy.
"I saw it coming. I mean everything," he said. "He said he was going to kill a whole bunch of people."
Ex-wife: He abused me
Mateen's first wife, Sitora Yusufiy, painted a damning portrait of the killer, describing a physically abusive marriage to a man with anger issues.
Yusufiy, who is originally from Uzbekistan, said the relationship started well after they met online about seven years ago.
"In the beginning, he was a normal being that cared about family, loved to joke, loved to have fun, but then a few months after we were married I saw his instability," she said.
"He would get mad out of nowhere. That's when I started worrying about my safety."
She said the abuse became a regular occurrence.
"He started abusing me physically, very often, and not allowing me to speak to my family, keeping me hostage from them," Yusufiy said.
"(My family) had to pull me out of his arms and find an emergency flight. ... I made a police report."
While her ex-husband was religious, Yusufiy said, she did not believe his religion played a role in the nightclub attack.
Married with a child
Mateen lived in a condo in Fort Pierce, Florida, with his second wife, a woman named Noor Salman, according to documents CNN obtained.
He also had a 3-year-old son, according to Mateen's father.
Mateen had worked for nine years as a security officer at G4S Secure Solutions, one of the world's largest private security companies.
According to a neighbor, he was a security guard at the St. Lucie County Courthouse, often manning the metal detectors at the front of the building.
Clarification: An earlier version of this story suggested Disneyland had beefed up security in response to the Orlando attack. After issuing a statement Tuesday morning about increased security, a Disney spokesperson later in the day said that the measures had been in place since December. The story has been updated to reflect this information.