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                                                                EXHIBIT 99(a)(1)




                  RIVERSIDE PARK ASSOCIATES LIMITED PARTNERSHIP
                         55 Beattie Place, P.O. Box 2347
                        Greenville, South Carolina 29602

                                  June 29, 1999

Dear Limited Partner:

         We understand that you will receive from MP Income Fund 15, LLC; MP
Income Fund 12, LLC; Accelerated High Yield Institutional Investors, Ltd.;
Accelerated High Yield Institutional Fund, Ltd.; Moraga Fund 1, L.P.; and Moraga
Gold, LLC (collectively, the "Bidders") an offer to purchase up to 60 limited
partnership units at $18,000 per unit of Riverside Park Associates Limited
Partnership (the "Partnership").

         The Partnership, through its general partner, Winthrop Financial
Associates Limited Partnership (the "General Partner"), is required by the rules
of the Securities and Exchange Commission to make a recommendation whether you
should accept or reject such offer, or whether the Partnership is remaining
neutral with respect to such offer. The General Partner is not making any
recommendation with respect to such offer for the reason set forth under "The
Offer -- Section 10. Position of Your General Partner of Your Partnership with
Respect to the Offer" in the enclosed Supplement, dated June 29, 1999, to the
Offer to Purchase, dated May 13, 1999, of AIMCO Properties, L.P. However, it
should be noted that such offer is at a lower price and for less units than the
offer being made by AIMCO Properties, L.P., which is for 168.14 units at $19,000
per unit.

         Please note that the General Partner is an affiliate of AIMCO
Properties, L.P.

         If you have any questions or would like further information about other
possible opportunities to sell your units, please contract River Oaks
Partnership Services, Inc. at (888) 349-2005.

                                       WINTHROP FINANCIAL ASSOCIATES
                                       LIMITED PARTNERSHIP
                                       General Partner


                                       By:  /s/ Patrick J. Foye
                                            -----------------------------------
                                            Patrick J. Foye
                                            Executive Vice President