"Simon Cabrera will remain in prison because we have strong evidence to incriminate him in this bloody event," Mueses told ESPNdeportes.com in Puerto Plata, where Simon is being held.
"Nothing has happened to make us change our position. This is a case for public action and we do not plan to dismiss the lawsuit," added Mueses.
Simon, 29, is being held for a year as a preventive measure for a year after being accused of shooting and killing Michel Castillo, 25, and wounding Castillo's brother Starlin, 17, in an incident during New Year's celebrations in the Dominican Republic.
Simon's lawyers applied for bail as part of a proposed plea, but the judge denied the request on Feb. 1.
A source related to the case told ESPNdeportes.com that Simon agreed to pay $2.6 million pesos, or $70,000 U.S., to the families of the Castillo brothers to withdraw the charges.
Mueses acknowledged the negotiations between Simon and the families but said they have not been reported to the prosecutors or Simon's lawyers.
"I do not know if there is an agreement, but if there's any action, it would be private and in no way affect our case. We do not have any new information that makes us think that things happened differently," Mueses said.
Mueses said he expects to receive the forensic report, including an autopsy of Michel Castillo and a ballistics report, soon.
Simon was 4-2 with a 4.93 ERA and 17 saves for the Orioles last season, where he served as Baltimore's closer for a portion of the season. He has appeared in 55 games for Baltimore over the last three years.
The Orioles placed Simon on the restricted list Friday, moving him off of their 40-man roster. Simon will not be paid or be credited for MLB service time while on the list.
Enrique Rojas is a reporter and columnist for ESPNdeportes.com and ESPN.com.