Try This;
PHP Code:
if(strcmp(cmd, "/drag", true) == 0)
    {
        if(IsPlayerConnected(playerid))
        {
            if(!IsACop(playerid))
            {
                SendClientMessage(playerid, COLOR_GRAD1, "You are not a cop!");
                return 1;
            }
            tmp = strtok(cmdtext, idx);
            if(!strlen(tmp))
            {
                SendClientMessage(playerid, COLOR_GRAD2, "USAGE: /drag [playerid/PartOfName]");
                return 1;
            }
            if(PlayerInfo[playerid][pDBanned] == 1)
            {
                SendClientMessage(playerid, COLOR_GREY, "** You are Banned From Cop Duty!");
                 return 1;
            }
            new newcar = GetPlayerVehicleID(playerid);
            new playa;
            playa = ReturnUser(tmp);
            if(IsACopCar(newcar) || IsNgCar(newcar) || IsAnFbiCar(newcar))
            {
                if(IsPlayerConnected(playa))
                {
                    if(playa != INVALID_PLAYER_ID)
                    {
                        new Float:x, Float:y, Float:z;
                        GetPlayerPos(playa,x,y,z);
                        if(IsPlayerInRangeOfPoint(playerid, 5, x, y, z))
                        {
                            PutPlayerInVehicle(playa,newcar,1);
                            GetPlayerName(playa, giveplayer, sizeof(giveplayer));
                            format(string, sizeof(string), "* %s drags %s to his/her car/moped.", sendername ,giveplayer);
                            ProxDetector(30.0, playerid, string, COLOR_CHAT1,COLOR_CHAT2,COLOR_CHAT3,COLOR_CHAT4,COLOR_CHAT5);
                            new y1, m, d;
                            new h,mi,s;
                            getdate(y1,m,d);
                            gettime(h,mi,s);
                            format(string,sizeof(string), "(%d/%d/%d)[%d:%d:%d] %s [CMD] -> /drag %s",d,m,y1,h,mi,s,sendername,giveplayer);
                            CommandLog(string);
                        }
                        else
                        {
                            SendClientMessage(playerid, COLOR_GREY, "Player is not near you.");
                        }
                    }
                }
            }
            else
            {
                SendClientMessage(playerid, COLOR_GRAD1, "You are not in police vehicle!");
            }
        }
        return 1;
    } 
 
Or  This!
PHP Code:
CMD:drag(playerid, params[])
{
    if(IsACop(playerid))
    {
        new string[128], giveplayerid;
        if(sscanf(params, "u", giveplayerid)) return SendClientMessageEx(playerid, COLOR_GREY, "USAGE: /drag [playerid]");
        if(IsPlayerConnected(giveplayerid))
        {
            if(GetPVarInt(giveplayerid, "PlayerCuffed") == 2)
            {
                if(IsPlayerInAnyVehicle(playerid)) return SendClientMessageEx(playerid, COLOR_WHITE, " You must be out of the vehicle to use this command.");
                if(GetPVarInt(giveplayerid, "BeingDragged") == 1)
                {
                    SendClientMessageEx(playerid, COLOR_WHITE, " That person is already being dragged. ");
                    return 1;
                }
                new Float:dX, Float:dY, Float:dZ;
                GetPlayerPos(giveplayerid, dX, dY, dZ);
                if(!IsPlayerInRangeOfPoint(playerid, 5.0, dX, dY, dZ))
                {
                    SendClientMessageEx(playerid, COLOR_GRAD2, " That suspect is not near you.");
                    return 1;
                }
                format(string, sizeof(string), "* %s has is now dragging you.", GetPlayerNameEx(playerid));
                SendClientMessageEx(giveplayerid, COLOR_WHITE, string);
                format(string, sizeof(string), "* You are now dragging %s, you may move them now.", GetPlayerNameEx(giveplayerid));
                SendClientMessageEx(playerid, COLOR_WHITE, string);
                format(string, sizeof(string), "* %s grabs ahold of %s and begins to move them.", GetPlayerNameEx(playerid), GetPlayerNameEx(giveplayerid));
                ProxDetector(30.0, playerid, string, COLOR_PURPLE,COLOR_PURPLE,COLOR_PURPLE,COLOR_PURPLE,COLOR_PURPLE);
                SendClientMessageEx(playerid, COLOR_WHITE, "You are now dragging the suspect, press the '{AA3333}FIRE{FFFFFF}' button to stop.");
                SetPVarInt(giveplayerid, "BeingDragged", 1);
                SetPVarInt(playerid, "DraggingPlayer", giveplayerid);
            }
            else
            {
                SendClientMessageEx(playerid, COLOR_WHITE, " The specified person is not cuffed !");
            }
        }
    }
    else
    {
        SendClientMessageEx(playerid, COLOR_GREY, "   You are not a LEO ! ");
        return 1;
    }
    return 1;
} 
 
Enjoy