ARDMORE, Oklahoma -- Texas Democrats who exiled themselves in Oklahoma to thwart a Republican congressional redistricting plan neared victory on Thursday, as republicans conceded the bill would die after midnight.

The showdown reverberated in Washington, where a Department of Homeland Security Agency said Texas police misled it in seeking help to find a plane carrying the missing Democrats, and congressional democrats demanded an investigation.

The more than 50 runaway legislators said on Thursday they would cross the Red River back into Texas after the redistricting bill was killed in a parliamentary chokehold.

"Our hard-working Democratic House members will return soon to Austin and they will be at their desks tomorrow morning ready to pass important legislation," state Democratic Chairwoman Molly Beth Malcolm told Reuters.

Their walkout on Sunday night shuttered the legislature by denying republicans a quorum of 100 lawmakers -- the number required to do business in the 150-member House.

That stopped a vote on a plan championed by U.S. House of Representatives Republican leader Tom Delay, a Texan, that could take five or six democratic seats from the Texas U.S. Congressional delegation.

It was not clear how soon the rebel Democrats would leave Oklahoma. The bill they opposed would effectively be dead once House Speaker Tom Craddick adjourned Thursday's session, but some did not want to return until they were certain their gambit had paid off.

"I don't put anything past them. I don't anticipate we will be going back until midnight," Rep. Joe Moreno said. --- Missing Democrats ---

Craddick on Monday sent police including the famed Texas rangers to find the missing Democrats, most of whom avoided the lawmen by taking a bus over the border to Ardmore, Oklahoma.

In Washington, Rep. Jim Turner of Texas, ranking Democrat on the House select committee on homeland security, asked the new homeland security department to explain a newspaper report that it helped look for a plane carrying the Texas lawmakers.

"We created the Department of Homeland Security to track down terrorists, not law abiding citizens," Turner said.

The department's Bureau of Immigration and Customs enforcement said Texas police had asked it to help find a missing plane. It quoted a Texas Department of Public Safety official as saying, "We had a plane that was supposed to be going from Ardmore, Oklahoma to Georgetown, Texas. It had state representatives in it and we cannot find this plane."

Said the agency, "from all indications, this request from the Texas DPS was an urgent plea for assistance from a Law Enforcement Agency trying to locate a missing, lost, or possibly crashed aircraft." It said it had made some calls but could not find the plane. No agency aircraft was used.

Texas DPS spokesman Tom Vinger said authorities had used "routine, common investigatory practices" when asked by the Texas House to find the lawmakers. He declined to comment on the Customs Agency's statement.

It is the third time in modern Texas history that State Legislators have thwarted bills by denying quorum. The last came in 1979, when the 13 democratic state senators hid in an Austin garage to sink an attempt to switch the Texas primary date to favor Republicans.