One of the Sri Lankan suicide bombers that terrorized the country on Easter Sunday had targeted a Christian church, but by the time he arrived, the service was already over.

April 21 marked one of the bloodiest Easter Sundays in history after 253 people were killed and at least 500 injured when seven Sri Lankan terrorists blew up three Christian churches and three luxury hotels.

Bomber Mohammed Nasar Mohammed Azar tried to target St. Mary's Cathedral in Batticaloa that Sunday but thankfully arrived too late.

'He came in the car around 8.30am and they told him mass is over now,' Bishop Joseph Ponniah said to CNN. 'Then he went to the next church.

Sri Lankan Mohammed Nasar Mohammed Azar (pictured above in CCTV footage) targeted St. Mary's Cathedral in Batticaloa on Easter Sunday, but the service had already ended

The early mass time ended up saving the lives of hundreds of worshipers, who were back home by the time Azar arrived

The early mass time ended up saving the lives of hundreds of worshipers, who were back home by the time Azar arrived.

Azar pictured on a mosque's security camera hours before the attacks

Then he went to Zion Church, a nearby evangelical congregation in Batticaloa.

In front of Zion church he detonated his bomb, killing 29 people and injuring 70 others.

Harrowing CCTV footage shows the moment Azar walks into the church at 8.51am in a pink polo shirt, sweatpants, while wearing a heavy backpack.

When he arrived to Zion church dozens of children had just finished Sunday school and some were playing outside, enjoying a breakfast before the main mass began at 9am.

There were about 500 people sitting inside.

But he was denied entry by two church officials Ramesh Raju and Rasalingam Sasikumar. They said he looked suspicious and wasn't wearing proper church attire.

After stopping at St. Mary's, Azar headed to Zion chuch. Shocking footage shows children praying and singing together at Zion church moments before 14 of them were killed in his attack

The devastation: Azar was one of seven suicide bombers to terrorize the country, targeting three Christian churches and three luxury hotels

Shocking footage from the attacks show worshipers inside the damaged St. Anthony's shrine following the blast in Colombo on Sunday April 21

Dead bodies of victims lie inside St. Sebastian's Church damaged in blast in Negombo, north of Colombo, Sri Lanka

This Sunday in Sri Lanka, Catholics celebrated Sunday Mass in their homes for the second week running as churches remain closed amid fears of fresh attacks by Islamic extremists

'Ramesh and Sashee were both trying to stop him from entering the church,' Rajeevkaran Vimalaretnam, a 38-year-old sound technician for the church said to CNN. 'They had apparently refused permission for him to enter the church and asked him to leave.'

'I saw a man standing there with two bags wearing a cap and a t-shirt. His dress code - cap, the bag -- all of this looked out of place,' he added. 'I saw a man standing there with two bags wearing a cap and a t-shirt. His dress code -- cap, the bag -- all of this looked out of place.'

The officials inquired about his bag. Azar said he wanted to film the church service. The officials responded they needed to ask the pastor's permission first.

A man cries as he prays in the street near St Anthony's Shrine one week on from the attacks that killed over 250 people on Easter Sunday

Another view of St. Mary's church pictured above

Azar then detonated his bomb outside, killing the two church officials that stopped him and 14 children playing outside.

Raju and Sasikumar are now being hailed as heroes in their communities for stopping the bomber.

'If he had walked inside and made his way to the center, I would have died, too,' Vimalaretnam said.

'And the number of victims would have been in the region of 200 to 300 people,' he added.

This Sunday in Sri Lanka, Catholics celebrated Sunday Mass in their homes for the second week running as churches remain closed amid fears of fresh attacks by Islamic extremists.

Azar was one of the seven suicide bomber recruited by National Tawheed Jamath (NTJ) Islamist extremist group. The group has since aligned itself with ISIS.