The District of Columbia has had seven homicides in four days, the most since last summer, when a spate of 13 homicides in 11 days launched a months-long crime emergency. A 29-year-old man was killed in a triple shooting in Columbia Heights at 10 p.m. Thursday night, the third homicide of the day.

The deaths this week shattered a relatively peaceful summer in which the number of homicides, at one time this month, were the lowest they had been in more than 20 years.