The police did not identify either youth because they are minors.
The infant's parents also were injured in the hail of bullets that pierced their car as they were leaving a baby shower in the 400 block of Wisteria Drive.
Police described the shooting as an act of retribution for a May 31 attack in Redwood City on the 17-year-old by members of the Surenos gang. However, in what is being called a case of mistaken identity, the victims of Sunday's shooting were not involved in the May attack and were not the people whom the teens thought they were, police said.
The two teens were picked up Sunday after a manhunt that had police going door to door in East Palo Alto interviewing known gang members and parolees.
The pair were arrested in the 400 block of Larkspur Drive. Officers found three weapons at the home. In the process of the interrogations, the 17-year-old made statements implicating himself in the shooting, police said today.
The department is continuing to gather evidence to determine whether the 16-year-old or anyone else will also be charged with the homicide and shootings. Police would not say if the two teens are members of a gang.
The infant's mother, Ivonne Garcia Lopez, was released from the hospital so she could attend the press conference. She appeared using a walker.
Police Chief Ron Davis had announced a $25,000 reward for any information that could lead to the suspects' capture. Police chaplains conducted a vigil on the block where the shooting occurred Sunday afternoon.
Anyone with additional information about the triple shooting is encouraged to call or send a text message to East Palo Alto police at 650-409-6792.
Witnesses can also send tips to email@example.com.