TIU detectives also conducted a number of searches in Strabane on Saturday, November 19.
The 38-year-old was arrested under Section 41 of the Terrorisam Act in the Strabane area.
Three men, two aged 36, and a 28-year-old were arrested in Strabane on Friday evening.
All four remain in custoday at the Serious Crime Suite in Musgrave Police Station for questioning.
More than 1,000 residents were affected by the security alert, with children being unable to get to school and carers unable to reach vulnerable residents, politicians say.
While no homes were evacuated, the road into the residential area was closed for much of Friday.
The road has since reopened.
The attempted murder investigation continues and police are appealing to anyone with information to contact them on 101.
Additionally, information and media can be provided to police through the Major Incident Public Portal link: https://mipp.police.uk/operation/PSNI22A02-PO1
Information can also be provided to Crimestoppers anonymously on 0800 555 111 or online at: www.crimestoppers-uk.org
Chief Constable Simon Byrne and Assistant Chief Constable Bobby Singleton visited Strabane on Friday to show support for local officers.
Assistant Chief Constable Singleton said: “Our thoughts are first and foremost with the two police officers who were here last night serving their community.
“Fortunately they are left simply shaken by what happened last night, but we are treating this incident as a credible attempt to murder those officers. This is an attempted murder investigation.“While our investigation is at an early stage, a strong line of enquiry is that this attack this was carried out by the New IRA.”
He also acknowledged the local community, saying: “We have somewhere in the region of 1,000 residents who have been affected by that security alert.
“We take this opportunity to thank them for their patience.”Tags: