Police arrested a man suspected in a stabbing attack Friday at Berlin’s Holocaust Memorial that left a Spanish tourist seriously injured, police said. There was no immediate indication of a motive for the attack, which comes two days before Germans vote in a national election on Sunday. Police spokesman Florian Nath told a news conference that the attack happened at 6 p.m. “probably with a knife. Maybe with something else.” Nearly three hours later, a male suspect approached officers who had surrounded the memorial grounds. “He had blood on his hands and this made him very suspicious,” Nath said. Police...