PHILADELPHIA — A Philadelphia man suspected of killing three men in two apparently random ambush-style shootings in recent weeks was arrested Thursday morning during a raid on his West Oak Lane home, police said Friday. Derrick Jones, 21, was taken into custody at his home in the 6900 block of Forrest Ave. He has been charged with three counts of murder and related offenses. Investigators have not identified a motive for any of the crimes. “The motive is unknown,” said Homicide Capt. Jason Smith. “That is the burning question: Why did Mr. Jones murder in cold blood three males?” Jones, who was…