Incident is reported about 6:30 p.m. Monday.
Man was crossing the street Thursday.
Authorities suspect medical emergency.
Police presence to be increased today.
Unclear how canine became confined.
Shooting came after dispute escalated, police say.
Shooting apparently occurred indoors, police say
National Zoo shows off sloth on Sloth Day.
IGunpoint incident reported around 5:20 p.m.
Police said clashes broke out between opposing protesters.