Alex Ligertwood, the Scottish singer best known for his work with  Santana , has died at the age of 79. The news was confirmed in a statement from his wife Shawn Brogan, who said he passed away at his home in Santa Monica, California on April 30. “It’s with great sadness and heartache to announce the passing of my sweet dear Alex Ligertwood,” she wrote. “Alex died peacefully in his sleep with his doggy Bobo by his side.” “Alex was loved by so many,” she added. “If you knew him, you loved him. He touched so many with his extraordinary voice. He was all heart and soul.” Ligertwood had performed his final show just a few weeks earlier, capping a career that spanned six decades.…