Kansas City police Thursday searched a small lake near the home of missing 11-month-old Lisa Irwin.

Police say the search was not initiated by a tip, but rather an expansion of their search.

The search at Chaumiere Lake lasted only about an hour and nothing of significance was found, according to police spokesman Darin Snapp.

Earlier Thursday, Lisa's parents canceled a news conference and planned media walkthrough of their home, citing exhaustion.

"The last few weeks have been exhausting to everyone working on behalf of the Irwin family," lawyer Cyndy Short said in a statement. "Therefore, the consensus is we all need a rest ... All appointments in Kansas City today and tomorrow are being postponed until next week."

It was not clear whether the planned police interviewing and DNA testing of Baby Lisa's young brothers, scheduled for Friday, would also be postponed.

On Wednesday, Short told FOX News Channel that the boys, aged six and eight, would be re-interviewed by police about the night their sister disappeared from the family home in Kansas City, Mo.

The two boys were first interviewed on the day that Baby Lisa vanished. Short said that the authorities and Lisa's parents, Jeremy Irwin and Deborah Bradley, had been trying to find "a balance in terms of understanding the needs of these children ... and the need for law enforcement to have as much info as they can possibly get."

Short said the parents' trust of investigators was "waning" following accusations that they were involved in their daughter's disappearance. But "the trust is not gone," she added.

Baby Lisa's parents continue to be the subject of intense media and police scrutiny over their actions the night she disappeared.

Bradley admitted in several interviews that she drank between five and 10 glasses of wine Oct. 3, the night Baby Lisa vanished. She told FOX News Channel's Megyn Kelly it was possible she blacked out after drinking, but denied that anything could have happened to her daughter while she was drunk.

She also admitted she last saw her baby at 6:40pm local time, not 10:30pm, as she had originally told investigators. Baby Lisa, whose birthday is Nov. 11, was reported missing more than nine hours later -- around 4:00am -- after her father returned home from work and noticed she was gone.

Last week, an FBI cadaver dog searching the family home detected the scent of a human body, prompting a subsequent extensive search.

Police combed the home for 17 hours last Wednesday, eventually removing bags of evidence and carpets. They also used what appeared to be X-ray equipment during the probe, The Kansas City Star reported.

Last Friday, three Kansas City residents came forward to say that they saw a suspicious man walking the streets with an infant on the night that Baby Lisa disappeared.

Two other witnesses, who were not named, said they encountered a similar scene a few hours earlier.

Newscore contributed to this report.