A Crime Scene Investigator (also referred to as a CSI or an investigator) is a criminalist who performs field work to collect and analyze evidence.

The following is a list of known CSIs in the TV series set in Las Vegas, Miami and New York.

CSI Trainee

None.

Level 1 CSIs

• Walter Simmons

Level 2 CSIs

• Natalia Boa Vista
• Morgan Brody
• Sheldon Hawkes

Level 3 CSIs

• Horatio Caine
• Sara Sidle
• Greg Sanders
• Julie Finlay
• Nick Stokes
• D.B. Russell
• Mac Taylor
• Jo Danville
• Danny Messer
• Lindsay Monroe

Alumni

• Gil Grissom - Level 3 CSI.

Deceased

• Warrick Brown - Level 3 CSI.
• Tim Speedle- Level 3 CSI.
• Jesse Cardoza- Level 2 CSI.
• Aiden Burn- Level 2 CSI.
• Michael Keppler - Level 3 CSI.
• Holly Gribbs - CSI Trainee.

Other

• Riley Adams- Level 2 CSI/Resigned.
• Raymond Langston- Level 2 CSI/Resigned.
• Catherine Willows- Level 3 CSI/Resigned.
• Stella Bonasera- Level 3 CSI/Resigned.