The boys, aged 12 and 14, live locally and were bailed following questioning to allow officers time to complete their investigations.
Investigation Officer DC Gerallt Davies said: “Despite arrests having been made this inquiry is still in its infancy with a number of outstanding enquiries to still be fully investigated and completed.
“I would like to hear from any potential witnesses who were in the area of the school during the afternoon or early evening of Friday, February 28.”
Our Lady Immaculate RC School on Caernarfon Road reopened on Wednesday for all pupils except for nursery children whose room was damaged in the attack. Teachers had spent the weekend tidying and setting up a temporary room for the classes affected. A test was a carried out to see if there was any structural damage to the classroom.
The fire started in a shed before spreading to the detached building. The heat was so intense that light fittings were damaged and the room also suffered from smoke and heat damage.
Firefighters were informed of the fire at 7:30 pm and crews from Bangor and Menai Bridge fire services arrived at the scene. North Wales Fire Service spokeswoman said firefighters cut their way in through the roof to put out the blaze and were required to wear breathing apparatus due to the smoke. After a thorough investigation it was declared that the fire was started deliberately.
Ms O’Hanlon, who teaches at the school said: “This shed has no electrics or gas fittings so the fire must have been started deliberately in some way. We also have evidence of people on the playground in the hour or so from 6pm when the after school club closed for the day.” She said that another shed containing children’s bicycles was broken into and they were found when the fire service and police arrived on the playground.
A Facebook page called Our Lady’s School Appeal has been set up following the fire in the hope that ex-pupils and residents will donate to help the school out.
Donna Jeffreys, who set up the page said: “Following the recent fire at our old primary school of Our Lady’s, it has been suggested that this page be set up in order to show our support and to make a donation to the only catholic school in Bangor. “Please add as many people as possible to the group in order for us to raise as much money as possible. Let’s get this appeal moving, in just one hour we doubled the group’s members!” The group currently has over 350 members and has received pledges of over £500.
DC Gerallt Davies reminded the community to remain vigilant at all times and to report suspicious behaviour to police immediately on 101 or to phone Crimestoppers on 0800 555 111 and quote incident reference number RC14030529