PITTSBURGH — The district attorney on Wednesday asked a judge to join the campaign corruption case of state Supreme Court Justice Joan Orie Melvin to that of her sister and now-suspended aide Janine Orie

If the motions by Allegheny County Deputy District Attorney Lawrence Claus are granted, Orie’s Aug. 17 trial will be delayed and she will be tried alongside Melvin at a date to be determined. Melvin, 56, was ordered Tuesday to stand trial on seven charges — including four felony counts of diversion of services — after a two-day preliminary hearing that featured testimony from her former law clerks and others who said the justice ordered them to do campaign work on state time.

Claus contends Melvin illegally used her former Superior Court staff to do campaign work when she ran for the Supreme Court in 2003 and again in 2009, when she won a seat. Orie, 58, has been awaiting trial for months on charges that she directed some of that campaign work on Melvin’s behalf while serving on Melvin’s staff.

Orie has been suspended from her $67,000-a-year job as Melvin’s aide since shortly after she and a third sister, former Republican state Sen. Jane Orie, were charged in April 2010 in a separate but related campaign corruption case.

Jane Orie, 50, was sentenced in June to 2½ to 10 years in prison and later ordered to pay $180,000 in restitution for misusing her state-paid legislative staff to do political fundraising and campaign work from 2001 to 2009, when a whistle-blowing intern went to the DA’s office and spurred the grand jury investigation that eventually led to charges against all three sisters.

Janine Orie remains charged with conspiring with the former senator to have the lawmaker’s staff do campaign work for Melvin in addition to charges that she directed the illegal campaign work by Melvin’s staff.

Janine and Jane Orie were tried together in 2011, but that ended in a mistrial when the former lawmaker used forged documents to discredit a key witness. Jane Orie was retried alone this spring and convicted of charges involving the misuse of her staff and the forged trial documents — but was acquitted on all charges that she misused her staff to help Melvin’s campaigns.

Janine Orie’s retrial was delayed by the former senator’s retrial. Now her attorney, James DePasquale, said he’ll fight any more delays or efforts to join her case with Melvin’s.

“My position is this should all come to an end,” DePasquale said. “I’ve been told repeatedly this is going to be the last continuance.”