FBI agents executed several search warrants at three homes in the Dallas-Fort Worth area Sunday where the suspected gunman in the El Paso Walmart massacre had stayed.

One of the locations was reportedly the home of Patrick Crusius’ grandparents in Allen, Texas, where authorities shut down streets following the shooting.

In a news conference Sunday afternoon, FBI Special Agent Jeanette Harper said forensic processing had begun examining the evidence taken from the homes. She did not disclose what was found or confiscated, saying the investigation is ongoing.

TRUMP DECLARES 'HATE HAS NO PLACE IN OUR COUNTRY,' AS DEMS DEMAND RECALL OF CONGRESS

She added that interviews were being conducted in Dallas and San Antonio, adding that the suspect has no known contacts in El Paso. Harper said at this point there was "no credible intelligence" that the suspect was "part of a group."

Another FBI spokeswoman declined to provide The Associated Press with more details on the other locations where search warrants were executed.

Meanwhile, authorities have said the massacre that left at least 20 people dead and wounded more than two dozen was being investigated as a domestic terrorism case. Officials are also looking into whether hate crime charges against the suspect, who has also been charged with capital murder, are appropriate.

Investigators were examining an alleged manifesto that the 21-year-old is believed to have written and would indicate “a nexus to a hate crime.”

Sgt. Robert Gomez, a spokesman with the El Paso Police Department, told reporters Sunday afternoon that the motive remained under investigation. Police did not release the names or ages of the victims pending notification of next of kin. Gomez added that the suspect surrendered to officers on a sidewalk near the crime scene.

'PURE EVIL': EL PASO MAYOR REACTS TO SHOOTING

El Paso Mayor Dee Margo issued a local disaster declaration Sunday.

“This declaration of a local disaster activates the appropriate recovery efforts from the State necessary for the City to address the needs associated with this weekend’s tragedy,” Margo said.

He added, “The impact of the shooting left multiple deaths and injuries in addition to property damage. The City of El Paso faces an exhaustion of resources for long-term recovery, including mental health issues affecting the community and first responders.”

“Issuing a local declaration of disaster triggers financial and physical assistance, and activates the City and County of El Paso’s emergency management plan.”

Earlier Sunday afternoon, President Trump offered his condolences to the victims in Texas — as well as those from a mass shooting in Dayton, Ohio. early Sunday morning that saw nine people killed. In that case, the gunman was killed by police.

“Hate has no place in our country, and we’re going to take care of it,” Trump said from the airport in Morristown, N.J., before he returned to Washington.

The president has ordered the lowering of American flags at all federal government buildings until Thursday.

"I haven't been informed by the police or the FBI about this individual at all, other than knowing that he came from the Dallas area, he was deranged, he was evil, but I can assure you that I am convinced no one from El Paso would have ever done this," El Paso's Republican Mayor Dee Margo told Chris Wallace on "Fox News Sunday. "It is not our nature, our culture and I don’t know about him. Pure evil, as far as I can characterize it."

"It’s tough anyway you look at it. Nobody prepares for this. I certainly, as mayor, have not been prepared for something like this," he said earlier in the interview.

EL PASO SHOOTING LEAVES 20 DEAD, 26 INJURED; INVESTIGATORS PROBING POTENTIAL 'NEXUS TO HATE CRIME'

The mass shooting is "devastating for the community," John Bash, the U.S. Attorney for the Western District of Texas, who has been in "close consultation" with Attorney General William Barr, told reporters at a news conference on Sunday.

"We are conducting a methodical investigation with our partners, a careful investigation, but with a view towards bringing federal hate crimes charges...and federal firearms charges which carry a penalty of death," Bash told reporters at a press conference. "We are seriously considering those charges."

Bash said investigators are also treating the shooting as a "domestic terrorism case," and said, "We're going to do what we do to terrorists in this country — which is deliver swift and certain justice."

El Paso District Attorney Jaime Esparza said that the state charge against the suspect is capital murder.

MULVANEY ON MASS SHOOTINGS: 'I DON'T THINK IT'S FAIR TO LAY THIS AT THE FEET OF THE PRESIDENT'

"He is eligible for the death penalty. We will seek the death penalty," he said. "The loss of life is so great, we certainly have never seen this in our community. We are a very safe community. We pride ourselves on the fact that we're so safe, and certainly this community is rocked, shocked and saddened by what has happened here yesterday."

Police told reporters on Sunday afternoon that first responders removed all the bodies from Walmart, saying that most of the victims were killed inside the store and others were shot in the parking lot.

The police department in Crusius' hometown of Allen said they had few past interactions with the suspect, saying it "can be described as limited at best."

In a statement, Allen police said Crusius was reported as a juvenile runaway in 2014 but returned home roughly a half-hour later. He was also among eight students on a school bus involved in a minor crash in 2016 that resulted in no injuries.

Allen police said their last involvement with Crusius came in March, when he reported a false residential alarm at his grandparents' home.

CLICK HERE TO GET THE FOX NEWS APP

The shootings over the weekend came less than a week after a 19-year-old gunman killed three people and injured 13 others at the popular Gilroy Garlic Festival in California before dying of a self-inflicted gunshot wound.

Anyone with information — including photos or videos of the scene — is urged to submit the content to the FBI at FBI.gov/ElPasoShooting.

Fox News' Lucia Suarez, Talia Kaplan and Nick Givas and The Associated Press contributed to this report.