[Patrick]

I did not really get what you mean, in my understanding, You want to show an admin a warning if the killer killed someone using a spraycan.

pawn Код:

//This callback gets called when the player dies.
public OnPlayerDeath(playerid, killerid, reason)
{
    if(killerid == INVALID_PLAYER_ID ) return false; //if the player is not connected or INVALID, this function will return nothing.

    if( GetPlayerWeapon(killerid) == 41)
    {
        return SendClientMessage(playerid, -1, "You have been killed by a spraycan"), SendClientMessage(killerid, -1, "You killed someone using a spraycan");
    }
    return true;
}

//This callback gets called when the player gets hit by a specific weapon.
public OnPlayerTakeDamage(playerid, issuerid, Float:amount, weaponid)
{
    if( weaponid == 41)//This function gets the player weapon id.
    {
        return SendClientMessage(playerid, -1, "You have been attacked by a spraycan"), SendClientMessage(issuerid, -1, "You attacked someone using a spraycan"); 
    }
    return true;
}