The 9-foot-deep garden pool where three children and a father drowned this week was originally designed to be 3 feet deep, a city official said, and an extensive safety review was planned.

Richard Zavala, parks and community services director, said the city will look into the discrepancy in the water depth and also evaluate whether an emergency pump shut-off valve should be closer to the pool.

Powerful suction apparently pulled the four victims to the bottom of the murky green pool at the Fort Worth Water Gardens (search) on Wednesday, authorities said.

The four, in town from Chicago for a Sunday school convention, had gone to the public fountains for relief from the sweltering weather because their hotel pool was closed.

Police say 8-year-old Lauren Dukes slipped and tumbled in. Her friend, 11-year-old Juantrice Deadmon, grabbed her hand but was pulled in. Then 13-year-old Christopher Dukes jumped in to help his sister and Juantrice.

At some point, the Dukes' father, 39-year-old Myron, also jumped in. After struggling to stay afloat, all four went to the bottom.

Police said the victims had obeyed signs warning against swimming in the fountains, waterfalls and pools.

"This was not the result of someone violating the law and going swimming. This looks as though it was an accident," Police Chief Ralph Mendoza said.

Before Wednesday, visitors were often seen wading, splashing or even taking a dip in the 5.4-acre park, which was designed by famed architect Philip Johnson and opened in 1974.

The pool where the four drowned is fed by water that flows down several irregularly spaced steps, creating waterfalls. The water is pulled through a drain at the pool's bottom by a pump, and the water is then recirculated through the structure.

The city has paid claims to people who have fallen down the steep steps, officials said. No injuries were serious enough to warrant erecting barriers, Zavala said.

Before Wednesday, the most serious accident at the park was in 1991, when an 80-foot light pole fell and killed two people.

City officials planned to meet with an engineering firm Friday to start the study. Officials said the Water Gardens, which have been drained, will remain closed until police finish investigating.

In Chicago's South Side, the steps of Antioch Missionary Baptist Church (search), where the victims worshipped, were piled with flowers and teddy bears.

Myron Dukes' sister, Georgia Dukes-Watson, said he and his wife, Stephanie Dukes, had gone to the convention with their two children to embrace their spirituality and take a break from their financial worries.

Myron Dukes was unemployed, she said, and his wife she would soon lose her telephone company job.

"They were really looking forward to enjoying themselves for a week before reality set in," Dukes-Watson told The Dallas Morning News. "It's just so horrendous, so tragic."

The church pastor, the Rev. Gerald M. Dew, who had also gone to the convention, said he was not angry at the city but stayed away from questions about possible legal action or the safety of the Water Gardens.

"My father told me once that God sends his best into the worst situations. We must be God's best," Dew said, wiping away tears.

He described Dukes as a caring family man who was active in church. The children were bright, energetic and loved church activities, especially the junior drill team, relatives said.