Raleigh Isaacs Jr. was convicted on Tuesday of refusal to take a blood or breath test, but a substitute judge dismissed a charge of driving under the influence stemming from the same incident.

It was the fourth time since March 2006 that Isaacs, the son of Suffolk’s sheriff, has been charged with driving under the influence in Suffolk. Every time, the charge has been reduced, dismissed or not prosecuted.

Isaacs was sentenced to a 12-month suspension of his driver’s license for the conviction, a sentence mandated by state law for the first refusal conviction.

The incident occurred on Aug. 28, when officers were dispatched about 11:30 p.m. regarding a possible drunken driver who had left the Ruby Tuesday restaurant on Godwin Boulevard after arguing with other patrons, city spokeswoman Debbie George said at the time.

Officers found the vehicle stopped in the middle of North Main Street and allegedly noticed a strong odor of alcohol and an open container of beer.

Isaacs also has been charged with driving under the influence in Suffolk in March 2006, October 2006 and June 2008.

In the first 2006 incident, he was charged with driving under the influence and reckless driving. The reckless driving charge was not prosecuted. The DUI charge was reduced to reckless driving, and he was given a 30-day suspended sentence and a $1,000 fine.

In October of that year, Isaacs was charged with driving under the influence, refusing to take a blood or breath test and reckless driving. The DUI and refusal charges were dismissed, and the reckless driving charge was reduced to improper driving. He received a 30-day suspended sentence and a $500 fine.

In June 2008, Isaacs was again charged with DUI, refusal and reckless driving after the van he was driving slammed into the front window of Pinner’s Flower Shop on West Washington Street, which had to close for four months. Charges of driving under the influence and refusal were not prosecuted in that wreck. Isaacs pleaded guilty to reckless driving, his license was suspended for six months, and he served 10 days in jail.

Tuesday’s court proceedings were moved to a Juvenile and Domestic Relations courtroom — where the public is normally barred from entry — because of the substitute judge, said Amanda Howie, a spokeswoman for the Norfolk Commonwealth’s Attorney’s office. The special prosecutor who handled the case, Mary Richardson, works in Norfolk.

Investigator E.C. Harris of the Suffolk Commonwealth’s Attorney’s office said the office does not keep statistics on the resolution of DUI cases.