His cause of death is unknown.
Under certain cicumstances it can.
He knew he had lost the war...so he shot himself.
Yes, under certain cicumstances and with pre-approval.
Leif Eriksson was killed in battle
Leif Hallberg died in 1960.
Leif Vetlesen died in 2003.
Leif Thybo died in 2001.
Leif Schiller died in 2007.
Leif Sörvik died in 1963.
Leif Haugen died in 2001.
Leif Næss died in 1973.
Leif Husebye died in 2009.