AUBURN, Maine — A Sabattus man who murdered his ex-girlfriend in 2005 is again seeking to have the state’s high court vacate his 2007 conviction in a bid for a new trial.

Daniel Roberts, 44, failed in his efforts to have his trial judge throw out his conviction after his attorney later argued that aspects of his trial were flawed, violating his constitutional rights.

Roberts had petitioned Androscoggin County Superior Court Justice Joyce Wheeler for a new trial or to send the case back to the Maine Supreme Judicial Court for a second look on appeal.

But Wheeler denied his post-conviction review and recently issued her final order on the case.

This will be the second time Roberts will be appealing to the state’s highest court. Unlike in his direct appeal in 2008, following his conviction and sentencing, the high court this time will consider whether he can show probable cause that there are grounds to vacate his conviction or other remedy, an additional hurdle to a straight appeal. The court could decline to hear his latest appeal.

Roberts shot to death Melissa Mendoza, 29, of California, in his garage on Aug. 15, 2005. The couple were embroiled in a custody dispute over their daughter, Savanna, 2 years old at the time of the shooting.

Roberts claimed the shooting was self-defense. But a jury agreed with prosecutors instead, who said Roberts had lain in wait for Mendoza.

Wheeler sentenced Roberts to 55 years in prison.

Wheeler, who presided over Roberts’ three-week trial in Androscoggin County Superior Court in 2007, heard arguments on his petition in 2011 before issuing her ruling in a 46-page order last year and in a 6-page supplemental order filed last week.

In her decision, Wheeler addressed Roberts’ six points outlined in his amended petition claiming violations of his constitutional rights.

They were:

* Right to a public trial;

* Right to freedom of association;

* Due process and fair trial rights;

* Ineffective assistance of trial counsel;

* Ineffective assistance of appellate counsel; and

* Right to due process and fair trial due to cumulative impact of errors.