Sinn Fein has condemned a bomb attack on a member of Strabane district policing partnership and urged anyone with information to contact police.
The bomb was left on Arthur McGarrigle's doorstep
Arthur McGarrigle said his son, who is in his 20s, saw two youths leaving the bomb at his home, and lifted it without realising the danger it posed.
Sinn Fein MP for West Tyrone Pat Doherty said the people behind such attacks had nothing to offer.
"There is absolutely no need for this type of activity whatsoever," he said.
"They should stop this. They should realise that big decisions have been made, that the vast majority of the community in the six counties who support the unification of Ireland have a political means and a peaceful means to achieve their objectives.
"This type of activity serves nobody. If people have information, they should tell the police."
Mr McGarrigle said the device, left at his home at about midnight on Wednesday, could have severely injured his family and caused extensive damage.
"The indication is that it was a viable device... it certainly wasn't left at my front door as a gift," he said.
A number of items were taken away for further examination after what was the third alert in the area in four days.
On Monday, a bomb was defused outside the Sion Mills home of former DPP member Mary McCrea.
On Sunday, a device was found at another home nearby.