DALLAS, Texas (CNN) -- A police officer was killed Friday morning in a motorcycle accident as Sen. Hillary Clinton's motorcade made its way through downtown Dallas, police said.



The Dallas Police Department said Senior Cpl. Victor Lozada-Tirado was traveling southbound on the Houston Street viaduct when he struck a curb, lost control of the motorcycle and went down.



Lozada-Tirado was transported to Methodist Central Hospital, where he was pronounced dead.



A Dallas police officer since December 1988, Lozada-Tirado was married with four children, according to police. CNN affiliate WFAA-TV in Dallas/Fort Worth reported he was 49.



There were no other vehicles involved in the accident, police said, and the motorcade was able to continue to the site without further incident.



Clinton said she called the Dallas police chief and would contact the officer's family at an appropriate time.



The Democratic presidential candidate said she is "greatly heartsick over this loss of life in the line of duty."



"I just want to express my deepest condolences to the family and to the Dallas Police Department on this tragic, tragic loss," she said.



"I am certainly grateful for all they do for me and more importantly what they do for the citizens of cities like Dallas."  Watch Clinton offer her condolences »



Clinton is attending rallies Friday in Texas and Ohio ahead of those states' primaries on March 4.



In the past 18 months, there have been two fatal accidents involving motorcycle officers escorting President Bush.



On August 27, Germaine Casey, an officer from Rio Rancho, New Mexico, died when his motorcycle crashed as the motorcade approached the airport in Albuquerque. The 40-year-old had been the lead motorcycle in the motorcade when the crash occurred.



On November 21, 2006, Steve Favela, a Honolulu police motorcycle officer, crashed on wet roads in Hawaii while part of the president's motorcade.



Favela, 30, died of his injuries a week later. Two other officers were injured in the crash. E-mail to a friend



CNN's Sasha Johnson and Mike Roselli contributed to this report.
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The Democratic presidential candidate The Democratic presidential candidate this loss of life Victor Lozada-Tirado Senior Cpl. Victor Lozada-Tirado Senior Cpl. Victor Lozada-Tirado Clinton's motorcade
question: Who is heartsick over this loss?, answer: The Democratic presidential candidate | question: Who is heartsick over the loss?, answer: The Democratic presidential candidate | question: Who is Clinton greatly heartsick over?, answer: this loss of life | question: Who died in motorcycle accident, answer: Victor Lozada-Tirado | question: Who died in a motorcycle accident?, answer: Senior Cpl. Victor Lozada-Tirado | question: Who has died in a motorcycle accident?, answer: Senior Cpl. Victor Lozada-Tirado | question: What was he part of?, answer: Clinton's motorcade