Luis Vielma was one of 50 victims tragically struck down in the Pulse nightclub massacre.
Omar Mateen killed 50 people and wounded 53 more when he opened fire at a gay nightclub.
Syed Shafeeq Rahman, a physician by profession, said he had known the gunman since he was an unruly child.
Florida Senator and former presidential candidate also said gun control not the right approach.
The president implores Americans to resist turning against each other after the Orlando nightclub shooting.
Mayor Eric Garcetti says the Los Angeles arrest appears unrelated to the Orlando massacre.
A squad of officers entered the club and shot dead the gunman, identified as Omar S. Mateen.