A Suffolk man pleaded guilty Wednesday morning to attempting to provide material support to a terrorist organization.

Lionel Nelson Williams, 27, twice attempted to send money to a person he believed was a financier for the Islamic State of Iraq and al-Sham, commonly known as ISIS, according to a press release from the U.S. Attorney’s Office for the Eastern District of Virginia. He believed the money would be used to kill.

As part of a plea agreement, Williams agreed he will receive the statutory maximum of 20 years in prison when he is sentenced on Dec. 20.

According to an affidavit filed in support of the charges, Williams sent money in October and November to a person he believed was collecting money for ISIS, the militant Islamic group that has claimed responsibility for terrorist attacks around the world, including in the United States.

Williams also ordered an AK-47 assault rifle on the day after the Dec. 2, 2015, terror attack in San Bernardino, Calif., according to the affidavit.

Williams lived with family members on Mineral Spring Road.

In late March 2016, a member of the public advised the Federal Bureau of Investigation that a former associate, later identified as Williams, had been posting videos and status updates supporting the terrorist organization on his Facebook page. The person also said Williams had recently acquired an AK-47 assault rifle.

The FBI reviewed Williams’ Facebook page and found the posts and the videos.

In one post on March 14, 2016, Williams wrote “The Jihad (the struggle) doesn’t end just because it stops feeling good.” Williams also included in his post a video of a lecture by Anwar al-Awlaki, the now-deceased leader of Al-Qaeda in the Arabian Peninsula.

Two days later, Williams posted “It’s time for me to take a stand. I stand with #Dawlah. If that means you want nothing to do with me, then fine.”

Dawlah is an Arabic term that means “state,” according to the affidavit.

On March 20, Williams shared a video posted by someone else, which featured a speaker who condemned Muslims who sided with Western states and Muslims who did not provide support for jihad.

“I love this video,” Williams commented. “I love the Mujahideen the world over.”

Mujahedeen is a term for Islamic fighters engaged in jihad.

On March 21, Williams liked a post by another Facebook user that expressed support for so-called “lone wolf attacks.” The post included the hashtag #KillThemWhereverYouFindThem.

Williams also posted a comment in response to this post that expressed support for targeting police officers, military and armed civilians, according to the affidavit.

On Jan. 13, 2016, an unidentified person contacted Suffolk Police Department to complain of hearing gunshots. Investigation revealed Williams had been target practicing near his residence. FBI aerial surveillance on April 25, 2016, observed two individuals leaving Williams’ residence and walking to a nearby series of outbuildings on the property. Infrared video captured what appeared to be muzzle flashes, according to the affidavit.

In late April 2016, an FBI-controlled persona friended Williams on Facebook and struck up a conversation. Williams told the person, “I can’t wait for the day that the black flag of Islam exists all over Maryland, D.C., Virginia and Chicago.”

On June 13, Williams met with an FBI undercover employee. He stated he supports attacks on “hard targets,” such as police officers, military personnel and others who have the ability to defend themselves.

He said he would want to target someone who could fight back, according to the affidavit.

In additional conversations with the FBI persona, Williams said he wanted to be a doctor or surgeon for the cause. Williams also agreed to donate money and provided $200 on a prepaid cash card.

The FBI persona later asked Williams if he wanted to see what his money helped purchase and sent a picture of what appeared to be a rocket propelled grenade.

He responded with an Arabic phrase meaning, “Praise be to Allah, and Allah is the Greatest,” according to this week’s press release.

Williams later sent $50 using an electronic transfer service to help purchase 10,000 rounds of AK-47 ammunition and 50 magazines.

Williams also discussed with the FBI persona of the possibility of conducting “martyrdom operations.” He stated his desire to marry and said he believed the marriage would ensure his “purity” so that any martyrdom operation he carried out would “lead to his true martyrdom, rather than simply his suicide,” according to the affidavit.

On Dec. 19, Williams wrote to the FBI persona that he was planning to empty his finances to “die without a single dollar in his pocket.”

Williams also responded that the plan was to do a “local” operation.

“It appears that Williams was moving closer to committing an attack that would result in his death,” the affidavit stated.

Williams was arrested on Dec. 21 in Suffolk. Agents located one semi-automatic handgun and one AK-47 semi-automatic rifle inside the residence.

After his arrest, Williams told agents he supported ISIS and believed he was part of a “holy war,” according to the press release.