Posted Monday, June 17, 2012 --- 3:00 p.m.

MILWAUKEE (AP) — Milwaukee police are investigating four weekend shooting incidents.

Three occurred within 35 minutes of each other early Saturday. But Capt. Michael D. Young says none of the four incidents appear to be related.

The Milwaukee Journal Sentinel reports the shootings injured five men, two of them critically.

The first incident, which occurred about midnight Saturday, involved an attempted street robbery in which a 45-year-old man was shot once in the chest.

The other three shootings happened in quick succession. Two men were wounded in an incident that police say began with an exchange of words inside Club Mix around 2 a.m. A fourth man was wounded during an alleged drug transaction around 2:15 a.m. Police weren't immediately sure what led to the fourth incident, about 2:35 a.m.

Copyright 2012 The Associated Press.