Updated

A Texas church that lost 13 members of its congregation after a bus collided head-on with a pickup truck has now set up a relief fund as authorities continue to investigate the cause of the crash.

“We are so grateful for the compassionate outpouring of support and prayers we have received since the tragic bus crash in which we lost 13 of our beloved church members,” the First Baptist New Braunfels Church posted on Facebook Thursday. “Many people have requested information on how to donate to support the victims' family members.”

THE WEEK IN PICTURES

Authorities in two Texas counties said Thursday that they received phone calls about a pickup driving erratically shortly before the accident with the church bus, which was heading home from a retreat.

"(The caller) was scared (the pickup driver) was going to cause an accident and asked us to send deputies," Uvalde police Lt. Daniel Rodriguez said. "Deputies were dispatched, but before they could reach the area, the same caller called 911 to report that the truck had been in an accident."

Dispatchers in Real County received a call from a woman who reported a truck was driving erratically on U.S. 83, county Constable Nathan Johnson said. Real County officials called Uvalde County officials to coordinate a response to send deputies. Then, the woman called back and said the truck that had been driving erratically had struck another vehicle before reaching Real County, Johnson said.

"Unfortunately, he struck a motor vehicle before anyone could respond," he said.

TEXAS CHURCH BUS CRASH: CALLERS REPORTED SWERVING PICKUP BEFORE COLLISION, POLICE SAY

The wreck unfolded along a curve in the road where the speed limit is 65 mph, DPS Sgt. Orlando Moreno said.

The Texas Department of Public Safety refused to speculate on the cause of the collision near the town of Concan, about 80 miles west of San Antonio, although one spokesman said the truck driver appeared to have crossed the center line.

The deadly accident has other churches in the area taking a second look at their safety protocols.

“Our hearts go out, our prayers go out to them just for God’s peace to be upon them and bless them and be with them as they work through this,” Roger Sharp, a pastoral assistance at RHEMA Bible Church in Broken Arrow, told KTUL.

The Oklahoma church has a fleet of buses used for community outreach, travel events and childcare services and plans to re-evaluate their operations.

“Relooking at your protocols, relooking at the rules. We try to meet all the standards and if we need to go beyond that, if there’s something we recognize then we try to comply with that also,” Sharp told the station.

Twelve bus passengers and driver Murray William Barrett, 67, died at the scene of the Texas crash Wednesday, DPS Lt. Johnny Hernandez said. Another bus passenger died at a San Antonio hospital. The pickup driver, Jack Dillon Young, 20, of Leakey, Texas, was still in stable condition and the lone survivor from the bus remained in critical condition Thursday night, DPS said.

CLUES EMERGE IN AFTERMATH OF DEADLY TEXAS CHURCH BUS CRASH

The collision was one of the deadliest in Texas in recent memory. Eight people were killed in May when a charter bus headed to a casino rolled over north of Laredo. In 2015, eight inmates and two corrections officers were killed when their prison bus skidded off a highway near Odessa, traveled down an embankment and was struck by a passing freight train.

Seventeen people died in 2008 when a charter bus crashed in North Texas near the Oklahoma border, and 23 nursing home residents being evacuated from the Houston area as Hurricane Rita approached in 2005 were killed when their charter bus caught fire near Dallas.

The Associated Press contributed to this report.