The column was based on public documents obtained by Lobdell, a former Pilot editor.
The city's current policy allows department heads to have a fellow supervisor or manager sign off on them, regardless of whether they're subordinates or superiors.
In Shawkey's case, Police Capt. Ron Smith approved his expense reports from February 2009 to November 2010, all of which claim the costs were for official business only.
According to city documents, Shawkey made several trips to Arizona, Utah and Wyoming in those 22 months. Shawkey was hired as police chief in 2007 from Phoenix, where he and his family lived. They now own a home in Coto de Caza.
It remained unclear this week whether the travel was for city or personal business and, if it was the latter, whether the money was paid back.
Acting-chief Capt. Les Gogerty said Tuesday that he's not aware of Costa Mesa police having official business in any of those locations and hasn't been required to go there as chief since taking over in November.
Roeder put Shawkey and Smith on leave in November for undisclosed reasons. Smith has indicated he plans to retire.
It is unclear whether the administrative leaves are related to the expense reports.
Smith and Shawkey have denied requests for comment in regards to the case.
Roeder expects to change the city policy this week, he said.
As for the city manager, Roeder said he hasn't submitted an expense report in 12 to 15 years.
However, he's considering changing the policy for how he would have them approved too. He suggested that he and City Council members make their discretionary expenditures available for public review every month.
Roeder plans to retire earlier this year. He will be replaced by his top deputy, Assistant City Manager Tom Hatch.