the inhabitants of Paradise from the inhabitants of Hellfire'

He published two blog posts on Monday, saying life is 'a test' to '

SWAT teams swarmed a house belonging to the family of a Muslim gunman who shot and killed four Marines during two brazen attacks on military sites that have been described as an 'act of domestic terrorism'.

Muhammad Youssef Abdulazeez, originally from Kuwait, first attacked a recruitment center at a strip mall with an automatic rifle on Thursday before driving seven miles north in a rented silver convertible Ford Mustang to a U.S. Naval Reserve Center.

There the 24-year old engineering graduate, who reportedly visited the Middle East in the last two years, fatally gunned down four Marines through a perimeter fence before a local police officer shot and killed him during a brutal standoff. At least three others were injured.

Hours after the shooting, law enforcement raided his family's house in the upscale neighborhood of Hixson, just a mile away from the scene of the first shooting, and took two women away in handcuffs.

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Smirking: Muhammad Youssef Abdulazeez, 24, has been identified as the gunman behind a shooting that killed four marines in Chattanooga on Thursday. He smiles in a mugshot (left) following his arrest for driving under the influence in April. Right he is pictured training as an amateur MMA fighter

Raid: Law enforcement officers detain a woman as they surround a house in Hixson, Tennessee, where gunman Youssef Abdulazeez lived for almost 17 years

Detained: FBI and a number of law enforcement officials stormed the house in the aftermath of the shooting

Investigation: Law enforcement personnel gather outside the home of gunman Mohammod Abdulazeez. FBI officials said no one else has been taken into custody and no one else is believed to be involved

Authorities remained at the property into the night as the FBI started a terrorist investigation in a bid to decipher the motives behind the attack, and discover whether he was inspired by ISIS.

It has also been revealed he updated a cryptic blog on his Islamic beliefs where he talked about submitting to Allah just three days before staging the horrific attack.

He wrote: 'Brothers and sisters don't be fooled by your desires, this life is short and bitter and the opportunity to submit to Allah may pass you by.'

According to The Daily Beast , he added: 'Take his (Allah's) word as your light and code and do not let other prisoners, whether they are so called "Scholars" or even your family members, divert you from the truth. If you make the intention to follow Allah's way 100 per cent and put your desires to the side, Allah will guide you to what is right.'

As a result of the shooting, security was beefed up across the country at military recruitment centers and bases.

The NYPD have also increased their presence at 'sensitive areas' - including recruitment centers and landmarks.

The attack came on the last day of the holy Muslim festival of Ramadan, a period during which ISIS agitators called for more lone wolf attacks.

Athlete: Muhammad Youssef Abdulazeez, left, is pictured with his fighting coach Scott Schrader after winning silver at the North American Grappling Championships

Family: Muhammad Youssef Abdulazeez (back row in orange shirt) poses for a picture with his family by the river banks of Chattanooga

Attack: The shooting started just before 11am on Thursday when witnesses saw a gunman pull into a local strip mall and start firing several rounds into the offices of a military recruitment center

Grief: A pastor prays over a sobbing citizen outside the recruitment center that was targeted during the attack

Abdulazeez was a practicing Muslim, and would take breaks from training as a Mixed Martial Arts fighter to pray in his coach's office.

Fellow worshipers had seem him in a local mosque up to a month before the attack, but it is not known if or how he may have been radicalized.

Those who prayed alongside him said he was acting normally and there was nothing to suggest he was preparing to do something so violent.

'There’s no Marine you would want that was better in combat than him

On Thursday evening, the FBI said no one else was believed to be involved and they hadn't taken anyone into custody. They added that they were yet to find any links to international terrorist cells, but were looking into every aspect of the shooter's life.

The first of the four casualties was named on Friday morning as a Purple Heart recipient.

Gunnery Sgt. Thomas Sullivan, from Springfield, Massachusetts, who received the honor for bravery during his two tours of Iraq, was confirmed dead by family members.

'There’s no Marine you would want that was better in combat than him,' his friend, Josh Parnell, told Patch . 'He’d been shot at so many times over the years and then for this to happen at home in the United States.'

The three other fatalities are yet to be named but are believed to have been part of a reserve artillery unit that had been deployed to Iraq three times.

Victim: Gunnery Sgt. Thomas Sullivan was the first victim fatality identified in the Chattanooga shootings

Wounded: Chattanooga Police Officer Dennis Pedigo has been identified as one of the people injured in the shooting. He is reportedly in stable condition at hospital

At least three others - including Chattanooga Police Officer Dennis Pedigo, a Marine recruiter and a Navy sailor - were injured. Pedigo is said to be in a stable condition.

The shooting started just before 11am on Thursday, when witnesses saw Abdulazeez drive into a strip mall and use a high-powered shotgun to fire more than a dozen rounds at a military recruitment office from his convertible Mustang. Only one person was injured in that attack and has been treated and released.

However, Abdulazeez drove on to a second site where his attack turned fatal. Fleeing the scene in his rented silver Ford Mustang, he drove to a U.S. Naval Reserve center where he opened fire again.

He killed four before he was gunned down in a hail of bullets after a short chase away from the scene. Reports suggest he held police at bay as he used 30-clip rounds from his automatic weapon.

Witnesses described seeing a police car riddled with bullets being towed away from the scene of the standoff.

Abdulazeez was a naturalized citizen who was brought up in Jordan and came to the United States with his family in 1996.

Happy student: Muhammad Youssef Abdulazeez attended the University of Tennessee, Chattanooga and graduated in 2012 with a degree in electrical engineering

Yearbook photo: Muhammad Youssef Abdulazeez wrote between two pictures of himself: 'My name causes national security alerts. What does yours do?'

Hobbies: A video purportedly shows him in a MMA fight in Chattanooga. (He is the fighter in the dark hair and camouflage shorts)

Opened fire: A member of the FBI looks at the glass doors riddled with bullet holes outside the recruitment center that was targeted in Chattanooga. It was the first of two military sites hit

A spokesman for the University of Tennessee, Chattanooga, confirmed that he attended the school and graduated in 2012 with a degree in electrical engineering.

Pictures on social media have emerged of him at his graduation ceremony and celebrating with members of his family in the same year.

However, he was recently seen smirking in his mugshot when he was arrested for driving under the influence in April. He was scheduled to attend a court hearing two weeks from the shooting.

Reports suggest he was stopped on the side of he road with 'white residue' on his face, while his car smelled of marijuana. He claimed he had crushed and snorted caffeine pills and refused a blood test.

In his yearbook entry for Red Bank High School, where he was a starter for the varsity wrestling team, he wrote between two pictures of himself: 'My name causes national security alerts. What does yours do?'

My name causes national security alerts. What does yours do?

According to online profiles and a YouTube video, he became an amateur Mixed Martial Arts (MMA) fighter when he left school.

Almir Dizdarevic, a former coach, told CNN he had traveled overseas to the Middle East in the last two years and had reportedly 'moved home'. However it is unknown where in the area he visited and why he was there.

Abdulazeez's father, Youssuf Abdullazeez, was appointed as a 'special policeman' for Chattanooga's Department of Public Works in March 2005, the Chattanooga Times Free Press reported.

He was investigated several years ago for allegedly giving money to a group associated with terrorism, the New York Times reported.

Citing unnamed law enforcement officials, the paper said the gunman's father was at one point on a terrorist watch list and was questioned while on a trip overseas.

The paper quoted an official as cautioning that the investigation was several years old and had not generated any information on the son. The father was eventually removed from the watch list, the paper quoted the official as saying.

Neighbors in the upscale community say his family were well-respected and the daughters would often babysit for their children.

A woman who was at school with Abdulazeez said he was a quiet kid, but well-liked.

Two attacks: The gunman initially opened fire on a recruitment center where he left one injured and then fled four miles north to a U.S. Naval Reserve center, where he killed four Marines

Terror attack: Officials confirmed four Marines were killed on Thursday when the gunman opened fire on two military sites. At least three others are said to have been injured

Investigating: Officials named the suspect, as 24-year-old Muhammad Youssef Abdulazeez, a naturalized U.S. citizen from Kuwait. The scene at the recruitment center is pictured

'Heartbreaking': President Obama released a statement saying it is 'a heartbreaking circumstance for these individuals that served our country with great valor to be killed in this fashion'

Karen Wagner told the Times Free Press: 'He was friendly, funny, kind,' said Kagan Wagner. 'I never would have thought it would would be him.'

'They were your average Chattanooga family,' she added.

Kevin Emily, his high school wrestling coach, told CNN he was just a 'normal', 'humble' student who would sometimes miss practice because he had to pray.

He described how his mother and father would come and watch his fights on a regular basis .

'There were no red flags about anything. We had a tight bond together.'

It is not known how and where he practiced Islam in the months before the attack but, according to the Daily Beast, he ran a rambling blog with only two posts, both posted on July 13.

The first post was entitled 'A Prison Called Dunya,' Abdulazeez refers to prisoner who is told he would be given a test that would either take him out of his earthly prison - or send him into a more restrictive environment.

According to the website, he wrote: 'I would imagine that any sane person would devote their time to mastering the information on the study guide and stay patient with their studies, only giving time for the other things around to keep themselves focused on passing the exam.

He added: 'This life is that test, designed to separate the inhabitants of Paradise from the inhabitants of Hellfire.'

The second post is called 'Understanding Islam: The Story of the Three Blind Men.' It suggests Abdulazeez felt his fellow Muslims had a 'certain understanding of Islam and keep a tunnel vision of what we think Islam is.

President Obama was briefed on the incident and immediately opened an investigation to be led by the FBI. The head of the government agency, James Comey, was said to have been inside the Oval Office when the president was informed of what happened.

Those inside were likely unarmed since a sign on the door said it was a gun-free zone

Deadly attack: The silver convertible used by Muhammad Youssef Abdulazeez was pictured at the scene of the second attack where he was shot dead

Response: Police officers with rifles kneel on the ground near the scene of the active shooting on Amnicola Highway in Chattanooga, Tennessee - near the Naval Reserve Center

Hail of bullet: Police opened fire and killed Muhammad Youssef Abdulazeez after his double attack that left four marines dead

Obama also urged the Department of Defense officials at bases around the country to remain 'vigilant' in the wake of the attack. This led to the beefing up of security in cities across the country.In a short statement, he said: 'It is a heartbreaking circumstance for these individuals that served our country with great valor to be killed in this fashion.'

He added that the thoughts of the American people are with the families of those who had been killed or injured.

Ray Mabus, the Secretary of the Navy said he would be opening an investigation into what happened, but insisted the families of the victims were the priority.

In a statement he said: 'Though we can never fully prevent attacks like this, we will continue to investigate, review and guard against future vulnerabilities and do everything in our power to safeguard the security of our service members and their families.

'While we expect our sailors and Marines to go into harm's way, and they do so without hesitation, an attack at home, in our community, is insidious and unfathomable. As the investigation unfolds, our priority will be to take care of the families of those affected.

Mabus also expressed his gratitude to the first responders who first went to the scene. He said their 'prompt reaction was critical to stopping this individual from inflicting further violence.'

On Thursday Secretary of Defense Ash Carter said: 'It is with a heavy heart that I learned of today's tragic events in Chattanooga.

'My thoughts and prayers - along with those of the men and women of the Department of Defense - are with the families of those killed in this senseless act of violence and with all those touched by this tragedy, including our Navy and Marine Corps family.

'I am grateful to local law enforcement for their swift response. The department will continue to work with local law enforcement as they investigate this heinous crime and will support our military families in their time of grief.'

Grief: Suzanne Burnett holds a candle as she sings during a prayer service at Wesley Memorial United Methodist Church for the victims of the shootings

Emotional: Chuck Hartung holds his daughter Haley, eight, during a prayer service in tribute to those who were killed or injured in the two brazen attacks

Prayers: The Rev. Drew McCallie prays during a prayer service at Wesley Memorial United Methodist Church. Members of the congregation hold their heads in worship at the end of the devastating day

Distraught: Local resident Chad Harris puts his face against a pew as he prays during the vigil

Mourning: Melody Kelley hugs Logan Wallace during the service as residents of the city reflect on the shooting

Response: Stephanie Rhoades holds her son Peyton as members of the congregation reacted emotionally to the violence

Tribute: Military veteran David Croft adjusts a US flag at a makeshift memorial near a US Military Recruiting storefront

Republican presidential hopeful Bobby Jindal released a strong statement, insisting the latest attack his proof that America is at war with everyday radical Islam.

He said: 'This apparent act of terrorism has taken the lives of four American heroes, and our hearts and prayers are with their families. While it's too early to know for sure what happened, it certainly looks like an act of terrorism.

'We must pursue justice on their behalf and stop at nothing to hunt down and kill these evildoers abroad before more of them come here to kill our people.

'This shooting underscores the grave reality of the threat posed to us by Radical Islamic terrorism every single day. It's time for the White House to wake up and tell the truth…and the truth is that Radical Islam is at war with us, and we must start by being honest about that.

'There have been many bad things that have happened under President Obama. One that stands out to me was the horrible shooting at Ft. Hood…which was clearly an act of terrorism by a Radical Islamist. Yet the White House labeled that horrible act as 'workplace violence.'

'This is grotesque. You cannot defeat evil until you admit that it exists.'

The Islamic community also came out to condemn the attack as 'cowardly'.

On Thursday, Bassam Issa, the President of the Islamic Society in Chattanooga, said: 'We are tremendously saddened by today's shooting in hour home town of Chattanooga, Tennessee. Our hearts are with the families of the brave Marines who died today and with the police officer and two bystanders who were shot and injured in this cowardly act.

'We condemn this act in the strongest possible terms as one of corwadice and hate. At the Islamic Center of Greater Chattannoga, we don't see our community center as a 'Muslim' community; we are Chattanoogans first, and we see ourselves as part of the larger community of Tennesseans grieving today's act.

'The leadership of the Islamic Society of Greater Chattanooga is currently meeting with law enforcement agencies and other members of the Chattanooga community in regards to this tragedy and will issue additional comments to the media this evening.'

Three days before Abdulazeez opened fire, local Muslims held a protest defending their religion in the Tennessee city.

They targeted Chattanooga because the FBI caught a man, called Robert Doggart, from there who was planning an attack on a Mosque in upstate New York.

He was indicted by a Tennessee grand jury on Tuesday for his involvement in the plot.

The shooting comes at a time of heightened security following terror warnings issued ahead of the Fourth of July weekend.

New York Police Department Deputy Commissioner Intelligence and Counterterrorism John Miller released a statement saying there would be an increased police presence in 'sensitive areas', including recruiting stations and landmarks.

'The NYPD has deployed an increased number of Critical Response Vehicles (CRV) to provide additional coverage at military recruiting stations and other sensitive locations in the City of New York.

'While we have no specific information about any plot against the city, until we learn more about the attack we have placed additional officers in key locations.'

'We have been in regular contact with Tennessee authorities, the FBI's Joint Terrorism Task Force and the intelligence community.

News of the shooting broke around 11:30am when Chattanooga Mayor Andy Berke tweeted: 'Horrific incident in our community. We will release details as they are confirmed. Prayers to all those affected'.

At an afternoon press conference, officials remained tight-lipped about details of the shooting, but said that it was being investigated as an 'act of domestic terrorism'.

They wouldn't divulge what kind of weapons the shooter was using, but did confirm that he had multiple weapons on his person.

The investigation is being coordinated by the FBI, since crimes on military centers are under federal jurisdiction.

Eyewitness, Gina Mule, who works near to the recruitment center said she saw the gunman fire at the offices.

Speaking to CNN, Mule said she was eating in a restaurant when a man 'with a high-powered rifle' began firing around 10:50am.

Huge response: Police and emergency vehicles block Amnicola Highway after the morning shooting near the Naval Reserve Center, in Chattanooga, Tenn. on Thursday, July 16, 2015

Increased security: An officer stands guard in front of a shuttered Navy recruiting center in downtown Manhattan

April Grimmett shared a picture of the bullet-ridden frontage of the recruitment center after hearing rapid gunfire coming from the vicinity.

'Shortly after that we heard the shot. It was very loud and very fast,' she said.

Grimmett added that the shooter appeared to be talking on the phone during the attack.

'I could not believe how many bullet holes were in that door. It was insane.'

One other witness, Erica Wright, told CNN that she was working in a hair salon near the center and saw and heard the gunman.

'We heard one pop, one really loud pop. We went to the door and there was several other pops after that and we looked two doors down and we saw a guy in a silver mustang unloading on the recruiter's office,' she said.

Wright added that he reloaded once or twice.

An unidentified man who was in the parking lot of the strip mall told WTVC about the terrifying situation that unfolded in front of him.

'He just pulled up. I didn't think anything of it. … He lifted up his arms with a big black gun. It was one shot then it was endless shots, one after another, just unloading.'

Marilyn Hutcheson was with her friend taking a break when she told CNN that she heard '7 to 15 shots'.

'There was a barrage of fire once the police officers and everyone got here,' she said. 'They came across and put all of the buildings on lockdown. There was a lot of gunfire going on for quite a while.'