A man has been arrested on suspicion of murder after a fatal stabbing in a street in west London, the Metropolitan police have said. A 20-year-old man was killed in stabbings in Brentford on Friday evening, which also left a 84-year-old woman seriously injured. Police were called to Albany Parade at about 7.50pm and found the man dead at the scene. Officers are supporting his family, the Met said. A witness told Sky News that the man had tried to challenge the attacker. The woman, who was reported to have been walking home from a friend’s house when she was attacked, was found with stab injuries and taken to hospital. Her condition was serious but not life-threatening, the force said. Police said a man aged in his 30s was arrested on Saturday morning on suspicion of murder and attempted murder. He remains in custody at a London police station. There was no evidence connecting the stabbings to terrorism, according to the force, which added that no one else was being sought over the incident. Officers are investigating whether either of the victims or the attacker were known to each other. Paul Moore, who lives nearby, told Sky News he helped the woman after she was stabbed. “She was walking home from her friend’s house and she thought the man had pushed her but she had been stabbed in the back,” he said. “She is a lovely woman. I’ve known her more than 30 years. Everyone knows her.” Homicide detectives from the specialist crime unit are leading the investigation. DCI Brian Howie said: “A number of cordons remain in place in and around Albany Parade, Albany Road and the surrounding area. Any local people who have information or concerns should speak with officers working at these locations. “I would like to hear from anyone who witnessed the incident or had any interaction with the suspect near the scene but has yet to speak with police. Anyone who may have footage, whether from doorbells, dashcams or mobile devices, is also urged to check that material and make contact with police should there be anything relevant to our investigation.” Anyone with any information has been asked to call 101.