A US Army Lieutenant who deserted to join the French Foreign Legion has been jailed for four years following a court martial.

Second Lieutenant Lawrence Franks, 28, graduated in second place from West Point military academy in 2008 before deserting the following year.

Lt Franks vanished from Fort Drum in New York state in 2009 and despite a massive search of nearby woods, there was no sign of any body.

Lieutenant Lawrence Franks, pictured deserted the US Army only a year after graduating from West Point

Lt Franks, centre rear, enlisted in the French Foreign Legion in March 2009 for five years

It later emerged that Lt Franks abandoned his post and flew to Paris before joining the French Foreign Legion.

He completed a five-year tour of duty under the assumed name Christopher Flaherty. At the end of his contract, he left the Foreign Legion and handed himself over the US Army in Germany, where he was sent back to the United States.

Neither the US Army or his family knew what happened to Lt Franks until he handed himself into authorities earlier this year.

The New York Times reported that Lt Franks was found guilty of conduct unbecoming of an officer and desertion as well as an intention to shirk his planned deployment to Afghanistan.

However, Lt Franks said that he did not want to wait 12 months for his own planned deployment. The 28-year-old former solider claimed he felt suicidal and would have shot himself if he had remained at Fort Drum.

Lt Franks said in an interview with the paper: 'I needed to be wet and cold and hungry. I needed the grueling life I could only find in a place like the Legion.”

'I feel really bad for the pain I put on my family, the disruption to my unit. But I don’t regret what I did — any of it, good or bad — because it saved my life.

Lt Franks, pictured, was jailed for four years after being found guilty of deserting the US Army

His former commanding officer with the Foreign Legion Brigadier General Laurent Kolodiej testified on Lt Frank's behalf by video. He said: 'We never ask where they come from. You have people knocking on the door, just make sure they don’t have blood on their hands, and we take them in. The Legionnaires, it’s about giving someone a second chance.'

Lt Franks said he had actively considered killing himself before leaving for France. He said he was planning an accident on the pistol range. However, a phone call to his family in March 2009 changed his mind and instead he decided to join the French Foreign Legion.

Retired Army psychiatrist Brigadier General Stephen Xanakis told the court martial that Lt Franks knew it was wrong to desert the US Army, but he considered suicide to have been a bigger sin.