Mr. Arredondo was at the finish line at the Boston Marathon with his wife, waiting for the last of the National Guard runners. They were representing Run For The Fallen Maine, an organization established to honor Marines who have been killed since the terror attacks of September 11th. One of those runners had dedicated the race to Mr. Arredondo’s son.

Immediately after the explosion, Mr. Arredondo vaulted a fence to help the wounded, many of whom had lost limbs, and used his clothes and towels to stop victims’ bleeding.

Mr. Arredondo was seen pulling debris and fencing away from the bloody victims, clearing the way for emergency personnel to tend to their wounds.

Mr. Arredondo helped one victim, Jeff Bauman Jr., who was missing both his legs and drenched in blood, into a wheelchair. He kept talking to the man so he wouldn’t lose consciousness.

His son, Marine Lance Corporal Alexander Arredondo (left) was killed in Iraq in 2004 by a sniper bullet. His brother Brian took his own life last year after struggling to deal with his elder brother’s death.

The day he learned his elder son had been killed, which also happened to be his 44th birthday, Mr. Arredondo ​locked himself in a van with five gallons of gasoline and a propane torch and set the van on fire. He was burned on 26 percent of his body and attended his son’s funeral on a stretcher.

After surviving the suicide attempt, Mr. Arredondo became a peace activist, as well as a suicide awareness advocate. He also changed his name to Alexander Brian Arredondo. In 2006 he became an American citizen.

By all accounts, this is a courageous and incredibly empathetic man who has lead a life with more tragedy than anyone should be asked to bear. I commend him for turning all that darkness into something positive, and for being one of those few people left who run toward an explosion when everyone else runs away (or gets out their cellphones).