That depends on the city and state you live in because each city has a set salary for their police officers pay and what they get paid by order of seniority. You should contact the website of that particularly city's police force normally in their FAQ they tell you what the average officer makes or look in the job description and it should tell you what the current salary is.
Law Enforcement Salaries
According to the Bureau of Labor Statistics' Occupational Outlook Handbook, (2006-07 Edition), patrol officers had median annual earnings of $45,210 in May 2004; median annual earnings of police and detective supervisors were $64,430; and the median annual earnings of detectives and criminal investigators were $53,990. You can visit the site for more detailed information: http://www.bls.gov/oco/ocos160.htm.