Anderson was conducting the investigation near a barber shop in East Baton Rouge, and struggled with the shooting suspect before being killed, police said.
The Sheriff’s Office posted on its Facebook page Sunday that it was one year to the day that Anderson had helped deliver a baby on the side of a road.
“Seeing Declan celebrate his birthday today is a poignant reminder that Sgt. Anderson lives on in the countless ways he has positively impacted so many. Happy birthday Declan! We are blessed to have such a reminder of Sgt. Anderson's service to his community!” the post said.
Anderson began working at the Sheriff's Office in 1999. He was presented the Life Saving Award in 2010 for saving the life of a woman on Old Mississippi River Bridge and recognized for serving more than 60 high-risk warrants in 2013 as part of a SWAT team with no injuries or shots fired.
"Our hearts are broken as we grieve for one of our brothers," East Baton Rouge Sheriff Sid Gautreaux said.
A suspect was shot and injured during the incident. The condition of the suspect was unavailable. Authorities have not released the identity of the suspect.
"I think we are a very praying community and I think that thoughts and prayers are needed here and we come together just like we always do and always have," Baton Rouge police Chief Carl Dabadie added. "There's no doubt we won't here, also."
The Associated Press and ABC News contributed to this article.