Second class passenger
“Several of his companions told him they had seen Murdoch, one of the officers, shoot himself. Other survivors, he said, told him that several passengers had been shot by officers in trying to force their way into the lifeboats."
Triumph and Tragedy lists a “Wilhelms, Mr. Charles” from London, England, aged 32, embarking Titanic in Southampton and travelling second class. (Triumph and Tragedy, p. 349 (7.)) Encyclopedia Titanica adds that his occupation was a “glass bender,” he lived at “Neville Road, Forest Gate, London, where his wife was left” and that his destination was “New York (2270 Broadway)” having “bought ticket number 244270 for £13” (8.). Mr. Wilhelms left Titanic aboard lifeboat No.9 and was consequently not in the vicinity when the alleged suicide took place. However, he did hear several shots echo across the water on that fateful night and his acquaintances reported that Murdoch had committed suicide and passengers were shot.
Bill Wormstedt’s Shots in the Dark reprinted Mr. Wilhelm’s account from the April 21st, 1912 edition of The New York Times:
“Mr. Wilhelms declared that he had heard several shots fired on the Titanic after he left the ship, and that several of his companions told him they had seen Murdock, one of the officers, shoot himself. Other survivors, he said, told him that several passengers had been shot by officers in trying to force their way into the lifeboats.” (12.)
The full article includes a description of the disaster that is a generally accurate and an unemotive account, including a description of the ship breaking in two:
"We rowed about 400 yards from the ship before we saw her settling slowly by the head. Then there was an explosion. The lights went out and the ship seemed to break, her nose plunging down and her stern bucking almost straight up.
Unfortunately, there are no details as to the sources of Mr. Wilhelms’ information regarding a shooting and suicide.
Second hand information ("several of his companions"). No known reason to doubt reliability.