The man arrested carrying a knapsack full of knives near the 10 Downing Street  was a passenger on the Mavi Marmara when it was raided by Israeli soldiers in 2010.

The suspect arrested Thursday on suspicion of planning a terrorist act was identified on Friday as Khalid Omar Ali, 27, of London,  the Telegraph reported on Friday.

Reuters reported that Ali was on the Mavi Marmara, as well as other aid flotillas to Gaza.

The Telegraph cites a former associate of Ali as saying that his experiences delivering aid to such a war-torn area may have left him disturbed and possibly suffering from some form of post-traumatic stress disorder.

He reportedly was under surveillance by police  when he was picked up near the prime minister’s official office on Thursday. Police reportedly had been watching him after receiving a tip from his family that he was behaving erratically .

After being on the Mavi Marmara when nine Turkish nationals were killed during the raid by Israeli naval commandoes, Ali was on board the Greek-flagged Strofades IV bound for Gaza from Libya, which sailed to Greece but did not continue on to Israel.

“Khalid was a happy, smiley person who was very easy going. He had a genuine desire to help people. But perhaps his experiences took their toll on him and he has suffered some sort of post-traumatic stress disorder,” a member of that group told The Telegraph.

His arrest came slightly more than a month after and 100 yards  from the spot where Khalid Masood was shot and killed after launching a deadly terror attack on the British Parliament.

Footage of Ali on the aid convoy to Gaza was published by The Daily Mail: