An Irish builder with IRA links has been jailed for 18 months on weapons, immigration and tax fraud charges in Pennsylvania.

Sean O'Neill, from County Tyrone, also faces deportation to Ireland after he finishes his sentence as it was revealed during the gun investigation that he had lied about his IRA past on immigration forms.

The gun charges stemmed from the fatal shooting of Scott Sheridan who was shot dead by O'Neill's son Sean during a drunken game between the two friends in 2006.

During the probe into the shooting, federal officials discovered that Sean Sr, 49, had lied on his application for a green card by concealing his links to the IRA youth group Fianna Na h'Eireann.

Sean Junior, now 20, shot his school friend, Scott Sheridan, while playing with his father’s gun.

Police said Sean’s blood-alcohol level was 0.175 at the time, more than twice the adult legal limit.

Sean was found guilty of juvenile manslaughter and spent nearly a year behind bars.

Prosecutors said O'Neill lied about his involvement with the IRA-linked youth group when he came to the U.S. in 1983. They say he married under false pretences just so he could stay here and then married his current wife, Eileen, without ever getting a divorce from his first wife.

Prosecutors argued that the Irishman lived in the U.S. illegally and made $13 million through his construction company and bar. He also purchased 17 properties, a helicopter and a number of fancy cars

The O'Neill family is mired in legal difficulties.

O’Neill’s daughter, Roisin, 23, is also charged with killing a Massachusetts grandmother after she drove up the wrong way on a high way while intoxicated.

O’Neill was ordered to report to prison on January 5th, 2010.

District Judge William Yohn also instructed O’Neill to pay $392,593 in back tax, a fine of $60,000 and a $500 dollar special assessment fee.