NEW ORLEANS — Concerned the Superdome might not be able to handle the energy needed for its first Super Bowl since Hurricane Katrina, officials spent hundreds of thousands of dollars on upgrades to decayed utility lines, according to documents obtained by The Associated Press.

The improvements apparently weren’t enough, however, to prevent an embarrassing and puzzling 34-minute power outage during the third quarter of the game between the Baltimore Ravens and San Francisco 49ers on Sunday.

Two days later, officials still had not pinpointed the cause of the outage.

The Superdome’s management company, SMG, and the utility that supplies the stadium, Entergy New Orleans, announced Tuesday that they would hire outside experts to investigate.

“We wanted to leave no stone unturned,” Entergy spokesman Chanel Lagarde told the AP. He said the two companies had not been able to reach a conclusion on the cause and wanted a third-party analysis.

SMG Vice President Doug Thornton told a news conference at City Hall later Tuesday that the hiring of a third party does not signify a disagreement between SMG and Entergy.

Documents obtained Monday through a records request by The Associated Press show that Superdome officials worried months ago about losing power during the NFL championship.

Tests on the electrical feeders that connect incoming power from utility lines to the stadium showed decay and “a chance of failure,” state officials warned in a memo dated Oct. 15.

The documents, obtained by the AP through a records request, also show that Entergy expressed concern about the reliability of the service before the Super Bowl.

Authorities subsequently authorized spending nearly $1 million on Superdome improvements, including more than $600,000 for upgrading the dome’s electrical feeder cable system, work that was done in December.

RAVENS: Baltimore celebrated with its Super Bowl champion Ravens, with thousands of fans in purple lining the streets and packing the team’s stadium for a celebration.

Fans filled the square in front of City Hall and cheered when the team arrived and when players held the silver Lombardi trophy aloft.

The Mayor’s Office of Emergency Management estimated that 200,000 people took part in the celebration in Charm City, including at City Hall, along the parade route and at the stadium.

GIANTS: New York released linebacker Michael Boley after four seasons with the team.

The 30-year-old Boley appeared in all 16 games last year with 11 starts.

He played a major role in the Giants’ victory over the New England Patriots in last season’s Super Bowl, making 10 tackles.

COWBOYS: Dallas promoted Wes Phillips to tight ends coach and hired Frank Pollack as assistant offensive line coach.

LIONS: Detroit released two veteran starters, cutting defensive end Kyle Vanden Bosch and guard Stephen Peterman.

JETS: New York fired offensive line coach Dave DeGuglielmo, and hired former NFL punter Louie Aguiar as an assistant as Rex Ryan filled out his coaching staff.

BROWNS: Cleveland released defensive end Frostee Rucker after one season.

JAGUARS: Jacksonville has a new logo .

The new logo maintains traditional colors (black, teal and gold) and offers a more realistic and fierce jaguar head.